hashtags. Searchable hashtag system, so if people wanted to have #speedrunners or #nintendo or #glassblowing then it would help with discovery and exploration of the site without expanding gaming categories to an excessive level.
Twitch's Creative category used to do this (the streamers, never support from the site itself.. they thought Communities would fill that gap, I guess, but..) in order to further identify what they were doing.
If we could attach a select number of hashtags to our streams it would help group us together as well as provide easy discovery of other likeminded streams.
If I were going to do some work on a tabletop RPG campaign, for instance, I could use the D&D category or I could use Writing and have hashtags #worldbuilding #dungeonworld #smallstreamer, etc.
What do you think?