kleinbl00 has outlined his vision for tags and crowdsourcing relatedness of tags numerous times before. It's brilliant. I can't find a link right now though and I really need to go to bed. Being able to have actual related tags or parent tags or whatever sort of connect-the-dots mechanism for tags would be amazing in an ideal world. Knowing that #writebetterdammit and #writebetterdamnit and #writing are related. Seeing those tags when you visit another. Seeing that 'dammit' is used more than 'damnit'. Etc. Etc. Etc. I love thinking about it. I love hearing other peoples ideas about it. I love everything about doing "what ifs..." and ignoring all practicality. But, logistically speaking, at best we're talking machine-learning madness and at worst we're talking a verifiable, crowdsourced, gamified algorithm program that allows people to start connecting all the dots for us.
Probably the most in-depth discussion. Well aware that this entire tirade is the coding equivalent of "and then you invent flying cars and it's f'n awesome."
Hierarchical clustering on tags based on cooccurence (cheapish, not that hard to implement), and KNN of post texts (not easy, but you're already doing the hard parts to implement decent search) takes you most of the way there if you're willing to go without negative feedback. That's not very mad.But, logistically speaking, at best we're talking machine-learning madness