Ah! I am extremely in favor of lots of tags as long as there are mechanisms to manage tag spam, and to collectively curate the folksonomy (so you don't end up with two tags for programming language and programming languages, for example). For the former I think tags should have profiles and bios, so we can as a community agree on and articulate what each tag is for. For the spam problem I think the best solution is to be able to vote tags up and down, indicating whether a link supports a tag or not. As long as people can keep their own tags visible to themselves, legitimate disagreements with the community shouldn't cause much friction.
The folksonomy (what a wonderful word) is the absolute key. I've pointed out to mk several times that if it doesn't scale it's doomed and the primary disadvantage of tags is drift. We used to have a bunch of interesting stuff in #writebetterdammit but then the influx of newbies started populating #writing instead. Grouping tags is the bugbear of any online community. I like the way Pearltrees does it (a number of us were in discussions with them to do a client-side subreddit index) but it isn't without its faults either.
Perhaps upon typing a tag, it pulled out tags with that prefix in a dropdown menu; however in addition, a count of users that followed the tag were visible: ecology (22)
economics (231)
economy (14) Not sure about the numbers. That might be a double-edged sword. It might just be enough to show what tags are out there.
Before we start to add more on, I'd like to convince myself that we aren't under-utilizing what we already have. It's pretty obvious that community tags aren't being commonly used, and there are probably better ways that we can use the tags that we have to improve content discovery. The thought just came to me, but I can imagine users building and sharing tag trees. Not sure that I like it, but I do think we have only scratched the surface of what we can do with what we currently have.
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".
After 30 seconds of thought I imagined that profiles would be wiki pages that anyone could edit, with comments for resolving edit wars. Does that seem plausible? Even if we can't satisfy everyone on what a tag means, individuals don't have to follow the collective folksonomy. If I apply 'programming languages' but the community prefers 'programming language', my tag still exists. It's just less salient because it's just me voting for it. What do you think?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?