Ability to create shareable lists of topics
In a recent comment I made, I wanted to list all the topics that were specific to something that developed over time. I used the tag filter for it in this case, but I thought it would be a nice feature if you were able to manually select which topics to list.
https://tildes.net/list?topics=123,124,125 could be good (I don't know what the usual way to represent lists in URLs is).
And maybe it could also be extended to comments, so you could group topics and comments together similar to the way they're displayed on profiles.