I happened over to SO today and saw that there are still a fair few TeX questions being asked (and answered!) there. I left a few "try this on http://tex.stackexchange.com" comments, but I feel that those work best if they are added very soon after the question is asked (and before any answers are posted). So those who are a bit more regular visitors to SO might want to look out for such questions.
I also just asked about formal migration on meta.SO: Can SO questions on TeX be migrated to tex.SX?
Also, if anyone has a good comment that we could adopt as a default for leaving on such questions, please let us know (and format it suitable for cut-and-pasting, so ensure that URLs are fully visible).