diff --git a/.spellcheckerdict.txt b/.spellcheckerdict.txt
index 144253f7..77b63816 100644
--- a/.spellcheckerdict.txt
+++ b/.spellcheckerdict.txt
@@ -8,6 +8,7 @@ CalVer
 CC0
 Changelog
 changeType
+cid
 [Cc]odec('s)?
 contentHash
 cryptographic
diff --git a/pages/DSNP/Announcements.md b/pages/DSNP/Announcements.md
index 8010868b..6abe3aec 100644
--- a/pages/DSNP/Announcements.md
+++ b/pages/DSNP/Announcements.md
@@ -15,12 +15,14 @@ Each Announcement has an enumerated type for use when separating out a stream of
 | 2 | [Broadcast](Types/Broadcast.md) | a public post | YES | YES |
 | 3 | [Reply](Types/Reply.md) | a public response to a Broadcast | YES | YES |
 | 4 | [Reaction](Types/Reaction.md) | a public visual reply to a Broadcast | no | no |
-| 5 | [Profile](Types/Profile.md) | a profile | YES | no |
+| 5 | ~~[Profile](Types/Profile.md)~~<sup>b</sup> | ~~a profile~~ | ~~YES~~ | ~~no~~ |
 | 6 | [Update](Types/Update.md) | an update to content| YES | no |
 | 7 | [Public Key](Types/PublicKey.md) | a public key for secure communication | no | no |
 
 <sup>a</sup> Since DSNP version 1.2, social graph changes use [User Data](UserData.md) operations as described in the [Graph](Graph.md) section.
 
+<sup>b</sup> Since DSNP version 1.3, profile changes use [User Data](UserData.md) operations.
+
 ## Announcement Validation
 
 There is no guarantee that, at time of creation, a given Announcement will be from the `fromId` claimed in the Announcement.
diff --git a/pages/DSNP/Types/CID.md b/pages/DSNP/Types/CID.md
new file mode 100644
index 00000000..d1d7a24e
--- /dev/null
+++ b/pages/DSNP/Types/CID.md
@@ -0,0 +1,48 @@
+# CID
+
+A Content IDentifier is represented by the CID object type.
+
+## Serialization
+
+CID object serialization MUST conform to the following [Avro](https://avro.apache.org) schema:
+
+```
+{
+    "namespace": "org.dsnp",
+    "name": "CID",
+    "type": "record",
+    "doc": "Content IDentifier for external document",
+    "fields": [
+        {
+            "name": "cid",
+            "type": "string",
+            "doc": "Content IDentifier of document"
+        },
+        {
+            "name": "type",
+            "type": "int",
+            "doc": "Type of document"
+        }
+    ]
+}
+```
+
+## Generation
+
+### cid
+
+- MUST be a valid value per the [Content IDentifier](https://github.com/multiformats/cid) specification.
+
+It should be possible to locate the content item associated with a CID on a content-addressed distributed file system.
+
+### type
+
+- MUST be a supported DSNP linked document type.
+
+#### Supported Linked Document Types
+
+| Value | Description | Specification | Content Type | DSNP Version Added |
+| --- | --- | --- | --- |
+| 1 | Activity Content Profile with DSNP extensions | [DSNP Profile](../../ActivityContent/Types/Profile.md) | `application/json` | 1.3 |
+
+All other document type values are reserved for future expansion.
diff --git a/pages/DSNP/UserData.md b/pages/DSNP/UserData.md
index 5a3fca8f..13052845 100644
--- a/pages/DSNP/UserData.md
+++ b/pages/DSNP/UserData.md
@@ -19,6 +19,7 @@ DSNP implementations MUST support the following User Data Types:
 | <a name="private-follows">`privateFollows`</a> | 1.2 | `curve25519xsalsa20poly1305` |  [`DEFLATE`](https://en.wikipedia.org/wiki/Deflate) | [GraphEdge](Types/GraphEdge.md) |
 | <a name="private-connections">`privateConnections`</a> | 1.2 | `curve25519xsalsa20poly1305` | [`DEFLATE`](https://en.wikipedia.org/wiki/Deflate) | [GraphEdge](Types/GraphEdge.md) |
 | <a name="private-connection-prids">`privateConnectionPRIds`</a> | 1.2 | NONE | NONE | [PRId](Types/PRId.md) |
+| <a name="linked-cids">`linkedCIDs`</a> | 1.3 | NONE | NONE | [CID](Types/CID.md) |
 
 Data for each data type is initially formatted as a stream of Avro objects that should conform to the schema specified.
 Avro file- and block-level information (including in-stream schema) is omitted.
diff --git a/pages/SUMMARY.md b/pages/SUMMARY.md
index db8a0f1f..58126c71 100644
--- a/pages/SUMMARY.md
+++ b/pages/SUMMARY.md
@@ -8,17 +8,18 @@
     - [User Data](DSNP/UserData.md)
       - [Graph Edge](DSNP/Types/GraphEdge.md)
       - [PRId](DSNP/Types/PRId.md)
+      - [CID](DSNP/Types/CID.md)
     - [Batch Publications](DSNP/BatchPublications.md)
     - [Announcements](DSNP/Announcements.md)
         - [Tombstone](DSNP/Types/Tombstone.md)
         - [Broadcast](DSNP/Types/Broadcast.md)
         - [Reply](DSNP/Types/Reply.md)
         - [Reaction](DSNP/Types/Reaction.md)
-        - [Profile](DSNP/Types/Profile.md)
         - [Update](DSNP/Types/Update.md)
         - [Public Key](DSNP/Types/PublicKey.md)
         - [Migrated Announcements](DSNP/Migrated.md)
             - [Graph Change](DSNP/Types/GraphChange.md)
+            - [Profile](DSNP/Types/Profile.md)
     - [Operations](DSNP/Operations.md)
     - [State Change Records](DSNP/Records.md)
     - [Serializations](DSNP/Serializations.md)