Dynamic composite user identifier

A system comprising:

• a memory;
• and
• at least one hardware processor coupled to the memory and comprising instructions that causes the system to perform operations comprising:
• accessing a chat history between a first user account and a second user account, the chat history comprising a set of messages;
• ranking plurality of media items based on the set of messages of the chat history, the plurality of media items including at least a media item;
• selecting the media item from among the plurality of media items based on the ranking;
• and
• generating a composite identifier based on a first user identifier associated with the first user account, a second user identifier associated with the second user account, and the media item.

A non-transitory machine-readable storage medium comprising instructions that, when executed by one or more processors of a machine, cause the machine to perform operations comprising:

• accessing a chat history between a first user account and a second user account, the chat history comprising a set of messages;
• ranking plurality of media items based on the set of messages of the chat history, the plurality of media items including at least a media item;
• selecting the media item from among the plurality of media items based on the ranking;
• and
• generating a composite identifier based on a first user identifier associated with the first user account, a second user identifier associated with the second user account, and the media item.