Agreeing on and articulating what a tag is for sounds dangerously close to moderation. Who decides? Does the first person to use a tag have some autonomy? If I use a tag one way, but lots of other people use it after me in a different way, do they get priority? I'm skeptical.

That said, I am in favor of letting users have as many tags as they want within a given character limit. I don't see the point in just one. I think many tags, while maybe inviting spam, also democratizes the process a bit, which I am in favor of. I have had several arguments with Dear Leader about this. He always wins.

Let's remember that if a user is not using a tag in a way that I like, I can choose not to see their posts. But that makes me wonder if we can have a cross-ref like "ignore <user> + <tag>", but not either individually. Might be complex to understand for the casual user, but just trying to start a conversation about how to better customize one's experience.

Also, what about an autofill option in the tag field? That might help resolve having both "kitten pics" and "kitten pic".