Yes, please: if a CV thread helps you in a non-trivial way, then do acknowledge it. It's polite towards the participants at that thread, and it may even put CV on a few people's radar. And it's always better than just saying that "it's a standard result that XYZ" - if it was sufficiently nonstandard for you to look it up or ask about at CV, then the same may apply to your readers.
I have cited CV threads in a couple recent papers. Sometimes, I'll cite an answer to a specific question I posted. Sometimes, I'll ask and self-answer standard calculations so I can refer to them in the future. And I don't think I have ever cited a thread that I was not personally involved in, but if that was helpful, I'll happily cite that, too.
There is a little "cite" link underneath each question, which will give you a nice BibTeX entry for your citation.