SIOC Core Ontology Namespace
description: SIOC (Semantically-Interlinked Online Communities) is an ontology for describing the information in online communities. This information can be used to export information from online communities and to link them together. The scope of the application areas that SIOC can be used for includes (and is not limited to) weblogs, message boards, mailing lists and chat channels.
type: Ontology
type: Thing
version info: Revision: 1.35

Community
type: Class
comment: Community is a high-level concept that defines an online community and what it consists of.
disjoint with: Item
disjoint with: Role
disjoint with: User Account

Container
type: Class
comment: An area in which content Items are contained.
disjoint with: Item
disjoint with: Role
disjoint with: User Account
disjoint with: Usergroup

Forum
type: Class
comment: A discussion area on which Posts or entries are made.
subclass of: Container

Item
type: Class
comment: An Item is something which can be in a Container.
disjoint with: Container
disjoint with: Role
disjoint with: Space
disjoint with: User Account
disjoint with: Usergroup

Post
type: Class
comment: An article or message that can be posted to a Forum.
subclass of: Item
subclass of: Document

Role
type: Class
comment: A Role is a function of a UserAccount within a scope of a particular Forum, Site, etc.
disjoint with: Container
disjoint with: Item
disjoint with: Space
disjoint with: User Account
disjoint with: Usergroup

Site
type: Class
comment: A Site can be the location of an online community or set of communities, with UserAccounts and Usergroups creating Items in a set of Containers. It can be thought of as a web-accessible data Space.
subclass of: Space

Space
type: Class
comment: A Space is a place where data resides, e.g. on a website, desktop, fileshare, etc.
disjoint with: Item
disjoint with: Role
disjoint with: User Account
disjoint with: Usergroup

Thread
type: Class
comment: A container for a series of threaded discussion Posts or Items.
subclass of: Container

User
type: DeprecatedClass
comment: UserAccount is now preferred. This is a deprecated class for a User in an online community site.
subclass of: OnlineAccount
disjoint with: Container
disjoint with: Item
disjoint with: Role
disjoint with: Space
disjoint with: Usergroup
equivalent class: User Account
version info: This class is deprecated. Use sioc:UserAccount from the SIOC ontology instead.

User Account
type: Class
comment: A user account in an online community site.
subclass of: OnlineAccount
disjoint with: Container
disjoint with: Item
disjoint with: Role
disjoint with: Space
disjoint with: Usergroup

Usergroup
type: Class
comment: A set of UserAccounts whose owners have a common purpose or interest. Can be used for access control purposes.
disjoint with: Container
disjoint with: Item
disjoint with: Role
disjoint with: Space
disjoint with: User Account

about
type: ObjectProperty
comment: Specifies that this Item is about a particular resource, e.g. a Post describing a book, hotel, etc.
domain: Item

account of
type: ObjectProperty
comment: Refers to the foaf:Agent or foaf:Person who owns this sioc:UserAccount.
domain: User Account
range: Agent
inverse of: account

addressed to
type: ObjectProperty
comment: Refers to who (e.g. a UserAccount, e-mail address, etc.) a particular Item is addressed to.
domain: Item

administrator of
type: ObjectProperty
comment: A Site that the UserAccount is an administrator of.
domain: User Account
range: Site
inverse of: has administrator

attachment
type: ObjectProperty
comment: The URI of a file attached to an Item.
domain: Item

avatar
type: ObjectProperty
comment: An image or depiction used to represent this UserAccount.
domain: User Account
sub property of: depiction

container of
type: ObjectProperty
comment: An Item that this Container contains.
domain: Container
range: Item
inverse of: has container

content
type: DatatypeProperty
comment: The content of the Item in plain text format.
domain: Item
range: Literal

content encoded
type: DatatypeProperty
type: DeprecatedProperty
comment: The encoded content of the Post, contained in CDATA areas.
domain: Post
range: Literal
version info: This property is deprecated. Use content:encoded from the RSS 1.0 content module instead.

created at
type: DatatypeProperty
type: DeprecatedProperty
comment: When this was created, in ISO 8601 format.
domain: Post
range: Literal
version info: This property is deprecated. Use dcterms:created from the Dublin Core ontology instead.

creator of
type: ObjectProperty
comment: A resource that the UserAccount is a creator of.
domain: User Account
inverse of: has creator

description
type: DatatypeProperty
type: DeprecatedProperty
comment: The content of the Post.
domain: Post
range: Literal
version info: This property is deprecated. Use sioc:content or other methods (AtomOwl, content:encoded from RSS 1.0, etc.) instead.

earlier version
type: TransitiveProperty
comment: Links to a previous (older) revision of this Item or Post.
domain: Item
range: Item
inverse of: later version

email
type: ObjectProperty
comment: An electronic mail address of the UserAccount.
domain: User Account

email sha1
type: DatatypeProperty
comment: An electronic mail address of the UserAccount, encoded using SHA1.
domain: User Account
range: Literal

embeds knowledge
type: ObjectProperty
comment: This links Items to embedded statements, facts and structured content.
domain: Item
range: Graph

feed
type: ObjectProperty
comment: A feed (e.g. RSS, Atom, etc.) pertaining to this resource (e.g. for a Forum, Site, UserAccount, etc.).

first name
type: DatatypeProperty
type: DeprecatedProperty
comment: First (real) name of this User. Synonyms include given name or christian name.
domain: User Account
range: Literal
version info: This property is deprecated. Use foaf:name or foaf:firstName from the FOAF vocabulary instead.

follows
type: ObjectProperty
comment: Indicates that one UserAccount follows another UserAccount (e.g. for microblog posts or other content item updates).
domain: User Account
range: User Account

function of
type: ObjectProperty
comment: A UserAccount that has this Role.
domain: Role
inverse of: has function

group of
type: DeprecatedProperty
type: ObjectProperty
inverse of: has group
version info: This property has been renamed. Use sioc:usergroup_of instead.

has administrator
type: ObjectProperty
comment: A UserAccount that is an administrator of this Site.
domain: Site
range: User Account
inverse of: administrator of

has container
type: ObjectProperty
comment: The Container to which this Item belongs.
domain: Item
range: Container
inverse of: container of

has creator
type: ObjectProperty
comment: This is the UserAccount that made this resource.
range: User Account
inverse of: creator of

has discussion
type: ObjectProperty
comment: The discussion that is related to this Item.
domain: Item

has function
type: ObjectProperty
comment: A Role that this UserAccount has.
range: Role
inverse of: function of

has group
type: DeprecatedProperty
type: ObjectProperty
inverse of: group of
version info: This property has been renamed. Use sioc:has_usergroup instead.

has host
type: ObjectProperty
comment: The Site that hosts this Forum.
domain: Forum
range: Site
inverse of: host of

has member
type: ObjectProperty
comment: A UserAccount that is a member of this Usergroup.
domain: Usergroup
range: User Account
inverse of: member of

has moderator
type: ObjectProperty
comment: A UserAccount that is a moderator of this Forum.
domain: Forum
range: User Account

has modifier
type: ObjectProperty
comment: A UserAccount that modified this Item.
domain: Item
range: User Account
inverse of: modifier of

has owner
type: ObjectProperty
comment: A UserAccount that this resource is owned by.
range: User Account
inverse of: owner of

has parent
type: ObjectProperty
comment: A Container or Forum that this Container or Forum is a child of.
domain: Container
range: Container
inverse of: parent of

has part
type: DeprecatedProperty
type: ObjectProperty
comment: An resource that is a part of this subject.
inverse of: part of
version info: This property is deprecated. Use dcterms:hasPart from the Dublin Core ontology instead.

has reply
type: ObjectProperty
comment: Points to an Item or Post that is a reply or response to this Item or Post.
domain: Item
range: Item
sub property of: related to
inverse of: reply of

has scope
type: ObjectProperty
comment: A resource that this Role applies to.
domain: Role
inverse of: scope of

has space
type: ObjectProperty
comment: A data Space which this resource is a part of.
range: Space
inverse of: space of

has subscriber
type: ObjectProperty
comment: A UserAccount that is subscribed to this Container.
domain: Container
range: User Account
inverse of: subscriber of

has usergroup
type: ObjectProperty
comment: Points to a Usergroup that has certain access to this Space.
domain: Space
range: Usergroup
inverse of: usergroup of

host of
type: ObjectProperty
comment: A Forum that is hosted on this Site.
domain: Site
range: Forum
inverse of: has host

id
type: DatatypeProperty
comment: An identifier of a SIOC concept instance. For example, a user ID. Must be unique for instances of each type of SIOC concept within the same site.
range: Literal

ip address
type: DatatypeProperty
comment: The IP address used when creating this Item. This can be associated with a creator. Some wiki articles list the IP addresses for the creator or modifiers when the usernames are absent.
domain: Item
range: Literal

last activity date
type: DatatypeProperty
comment: The date and time of the last activity associated with a SIOC concept instance, and expressed in ISO 8601 format. This could be due to a reply Post or Comment, a modification to an Item, etc.
range: Literal
sub property of: date

last item date
type: DatatypeProperty
comment: The date and time of the last Post (or Item) in a Forum (or a Container), in ISO 8601 format.
domain: Container
range: Literal
sub property of: date

last name
type: DatatypeProperty
type: DeprecatedProperty
comment: Last (real) name of this user. Synonyms include surname or family name.
domain: User Account
range: Literal
version info: This property is deprecated. Use foaf:name or foaf:surname from the FOAF vocabulary instead.

last reply date
type: DatatypeProperty
comment: The date and time of the last reply Post or Comment, which could be associated with a starter Item or Post or with a Thread, and expressed in ISO 8601 format.
range: Literal
sub property of: date

later version
type: TransitiveProperty
comment: Links to a later (newer) revision of this Item or Post.
domain: Item
range: Item
inverse of: earlier version

latest version
type: ObjectProperty
comment: Links to the latest revision of this Item or Post.
domain: Item
range: Item

link
type: ObjectProperty
comment: A URI of a document which contains this SIOC object.

links to
type: ObjectProperty
comment: Links extracted from hyperlinks within a SIOC concept, e.g. Post or Site.
sub property of: references

member of
type: ObjectProperty
comment: A Usergroup that this UserAccount is a member of.
domain: User Account
range: Usergroup
inverse of: has member

moderator of
type: ObjectProperty
comment: A Forum that a UserAccount is a moderator of.
domain: User Account
range: Forum
inverse of: has moderator

modified at
type: DatatypeProperty
type: DeprecatedProperty
comment: When this was modified, in ISO 8601 format.
domain: Post
range: Literal
version info: This property is deprecated. Use dcterms:modified from the Dublin Core ontology instead.

modifier of
type: ObjectProperty
comment: An Item that this UserAccount has modified.
domain: User Account
range: Item
inverse of: has modifier

name
type: DatatypeProperty
comment: The name of a SIOC concept instance, e.g. a username for a UserAccount, group name for a Usergroup, etc.
range: Literal

next by date
type: ObjectProperty
comment: Next Item or Post in a given Container sorted by date.
domain: Item
range: Item
inverse of: previous by date

next version
type: ObjectProperty
comment: Links to the next revision of this Item or Post.
domain: Item
range: Item
sub property of: later version
inverse of: previous version

note
type: DatatypeProperty
comment: A note associated with this resource, for example, if it has been edited by a UserAccount.
range: Literal

num authors
type: DatatypeProperty
comment: The number of unique authors (UserAccounts and unregistered posters) who have contributed to this Item, Thread, Post, etc.
range: nonNegativeInteger

num items
type: DatatypeProperty
comment: The number of Posts (or Items) in a Forum (or a Container).
domain: Container
range: nonNegativeInteger

num replies
type: DatatypeProperty
comment: The number of replies that this Item, Thread, Post, etc. has. Useful for when the reply structure is absent.
range: nonNegativeInteger

num threads
type: DatatypeProperty
comment: The number of Threads (AKA discussion topics) in a Forum.
domain: Forum
range: nonNegativeInteger

num views
type: DatatypeProperty
comment: The number of times this Item, Thread, UserAccount profile, etc. has been viewed.
range: nonNegativeInteger

owner of
type: ObjectProperty
comment: A resource owned by a particular UserAccount, for example, a weblog or image gallery.
domain: User Account
inverse of: has owner

parent of
type: ObjectProperty
comment: A child Container or Forum that this Container or Forum is a parent of.
domain: Container
range: Container
inverse of: has parent

part of
type: DeprecatedProperty
type: ObjectProperty
comment: A resource that the subject is a part of.
inverse of: has part
version info: This property is deprecated. Use dcterms:isPartOf from the Dublin Core ontology instead.

previous by date
type: ObjectProperty
comment: Previous Item or Post in a given Container sorted by date.
domain: Item
range: Item
inverse of: next by date

previous version
type: ObjectProperty
comment: Links to the previous revision of this Item or Post.
domain: Item
range: Item
sub property of: earlier version
inverse of: next version

reference
type: DeprecatedProperty
type: ObjectProperty
comment: Links either created explicitly or extracted implicitly on the HTML level from the Post.
domain: Post
version info: Renamed to sioc:links_to.

related to
type: ObjectProperty
comment: Related Posts for this Post, perhaps determined implicitly from topics or references.

reply of
type: ObjectProperty
comment: Links to an Item or Post which this Item or Post is a reply to.
domain: Item
range: Item
sub property of: related to
inverse of: has reply

scope of
type: ObjectProperty
comment: A Role that has a scope of this resource.
range: Role
inverse of: has scope

sibling
type: SymmetricProperty
comment: An Item may have a sibling or a twin that exists in a different Container, but the siblings may differ in some small way (for example, language, category, etc.). The sibling of this Item should be self-describing (that is, it should contain all available information).
domain: Item
range: Item

space of
type: ObjectProperty
comment: A resource which belongs to this data Space.
domain: Space
inverse of: has space

subject
type: DatatypeProperty
type: DeprecatedProperty
comment: Keyword(s) describing subject of the Post.
domain: Post
range: Literal
version info: This property is deprecated. Use dcterms:subject from the Dublin Core ontology for text keywords and sioc:topic if the subject can be represented by a URI instead.

subscriber of
type: ObjectProperty
comment: A Container that a UserAccount is subscribed to.
domain: User Account
range: Container
inverse of: has subscriber

title
type: DatatypeProperty
type: DeprecatedProperty
comment: This is the title (subject line) of the Post. Note that for a Post within a threaded discussion that has no parents, it would detail the topic thread.
domain: Post
range: Literal
version info: This property is deprecated. Use dcterms:title from the Dublin Core ontology instead.

topic
type: ObjectProperty
comment: A topic of interest, linking to the appropriate URI, e.g. in the Open Directory Project or of a SKOS category.
sub property of: subject

usergroup of
type: ObjectProperty
comment: A Space that the Usergroup has access to.
domain: Usergroup
range: Space
inverse of: has usergroup

SIOC Core Ontology Specification