I'm still preparing for a 3 hour course I'm teaching next week on blogging. One of the questions people always have is "how will this affect me career?"
Dan Farber has a great post at Between the Lines on blogging as a potential career ender. That title probably overstates the case a little. The number of bloggers who get fired because of their blogs, or dooced is small as a percentage. That doesn't mean, however that your blog won't affect your career.
I can easily point to the place where my blog has had a positive impact on my career. It's hard to find the places that it's had a negative impact because I'm not likely to know when someone looked at it and decided not to offer me a job because of something I wrote.
The advice that Dan lists to from Scott Wilder is good and useful. I'll be using some of it next week.