This can cut both ways. One time I said something vaguely insulting (and in retrospect, insensitive) about Steve Wozniak on Slashdot, and he replied to the comment personally.
You never know who is reading, so don't say anything you couldn't vouch for in real life (which increasingly overlaps with our Internet life)
I did this on twitter once with Mike Masnick of techdirt. He certainly didn't follow me, must have a search with his name setup. Of all the situations to raise the ire of someone even moderately internet famous it was possibly one of the most petty too - and his response was way more mature than my call...oops.
You never know who is reading, so don't say anything you couldn't vouch for in real life (which increasingly overlaps with our Internet life)