I've participated in several new Stack Exchange (beta) sites, and they've all had this same problem (which is again current): developing the tag set. I'm talking here about tags that don't fit neatly into ontologies (like location tags). I'm talking about all the other ones, the tags that describe the content in a less-structured way.
These less-structured tags are emergent -- several questions get asked that have a theme in common, and somebody creates the tag and applies it to them. Sometimes the author of a question creates a new tag as part of asking the question. Sometimes there's duplication, sometimes there's odd overlap, and sometimes the vocabulary choices that are clear to one user are puzzling to another. The progression I'm used to seeing goes like this:
- Chaos: tagging is very haphazard and disorganized.
- First refinement, maybe with discussion: one or more users try to clean things up a little to lay a good foundation.
- More questions come in and flaws become more obvious.
- Second refinement, with discussion: somebody organizes the Great Tag Cleanup on meta.
- Tags limp along for a while, sometimes oscillating (use X / no this should be Y / eh maybe X was a better idea). Meanwhile, new questions come in, some of which don't fit any tags. (For example, this question doesn't seem to fit well with any of our tags.)
- Ongoing "spot" improvements -- breaking up that tag that's on 40% of the questions (as it turned out), create those synonyms, retag those, etc. User interest and results vary. Retagging questions can be disruptive (those edits bump posts), so there's a tradeoff between messing up the front page and fixing things, with uncertainty about how much of a fix it is.
I'm participating now on a beta that currently has fewer than 200 questions. On the one hand, if we can establish some good patterns now, it feels like it should be easier to have good tags as we progress. On the other hand, if we wait until we accumulate more questions, maybe we can skip some of the oscillation -- but we make more chaos in the meantime.
How do we know when it's time to tackle topic tags? Are there rules of thumb?
I'm specifically asking about a Stack Exchange site, but other multi-user platforms use tagging, so I welcome insight from elsewhere too.