I've been thinking more about tagging and the apparent problem so many people on SO seem to have with the concept. The number of times I've had to fix questions tagged
server, often for users with 3000+ reputation, defies reason. And that's just the tip of the iceberg.
It occurs to me that a lot of the problem is we've been trained by other sites to treat tags differently. Programmers generally know how to do categorization, but that's just not how they look at the tag metaphor on a web site. Sites like flikr and youtube need to also use tags for search indexing, and so they mix the categorization concept with a description concept, resulting in an impossibly fragmented tag inventory.
The solution here, then, is a simple name change — change the name, change the metaphor. I think more people get that labels (as in gmail) are about categorization, and using the term "label" will help them expect to find existing labels and look for the correct ones rather than type whatever pops into their head, as appears to happen so often right now.
I fully expect this to end up status-declined, as this "simple" cosmetic change touches question urls, and that means mvc routes in code, bookmarks, etc. At very least you'd have to leave the old routes around as duplicates for the bookmarks. But I would like to see if it could build up any support and hear others' thoughts on whether this would help.