Rebecca J. Stones top 3% overall
I use math.SE for: (a) teaching practice, (b) finding interesting research problems (e.g. this paper), (c) doing mathematics in a more social way, (d) learning new topics, (e) finding answers more quickly, and (f) fun.
If you want my email you can find it through the linked papers above. I'm happy to be contacted for research collaboration, otherwise I'm probably not interested (in which case, I won't reply).