It has happened so many times: I am curious about a certain product, say rate-my-shoes.com, sign up on their website and with in a few weeks, they are the 3rd or 4th result in Google when I look up my name, saying "Rate Seshadri's shoes here!".
Then I have to go back and look for some advanced setting where I disable search engine listing of my profile, or even delete the account completely if I don't find the option to disable my public profile or don't like the product enough.
So, please, please don't make my profile available to search engines by default or at least ask me if I want to do so !