As I commented on Josh K's answer (a good one to take into consideration mind you), it depends on the type of content that you put in via your stackoverflow account. You can generalize that to the type of content present on your identifiable internet presence. I would probably not do it, not because it is a bad idea (nor I feel my content is inapropriate), but because I'm already including my linkedin profile and tech blog in my CV.
Potential employers can then use that to discern what I've posted on SO, ServerFault or say, cstheory.stackexchange or even slashdot if they so wish. I try to create mostly good content but there are a couple of WTFs here and there. I don't worry about them. If my content however contained a high ratio of flamewards and LOLZ, then I would be worried.
I used to have one like that before under a pseudonym (younger, stupider days), but that has been completely replaced with more professional content under my actual name. The older one can still be found if one is really persistent, but then, unless I'm applying for, I dunno, a top secret gig or something like that, I would not be happy if an employer goes to that extreme of finding my much older content.
Neither would I accept to continue an interview or work with such a company. Probabilistically speaking, I doubt that such a thing is a common occurrence for employers worth working for (except for jobs with valid reasons to perform extensive background checks.)
So, it is a personal call whether to include a SO's profile on your CV. It depends on what type of content you have. My personal feeling is that I would prefer to have a well-maintained linkedin profile or tech blog, have it with links to other tech-oriented profiles of yours, and have that (your linkedin profile or a technical blog) included in your CV.