Privacy advocates have been vying with search engines for a while now, trying to establish some basic guidelines about how search engines like Google, Yahoo, and Bing can use and sell the information they gather about you. Some experts say six months should be the longest a search engine holds onto your information, but the majors currently hold onto data for as much as 18 months or longer.Over in Europe, there's been pressure for some time from regulators-with no solid commitments made so far from the major players on the business side. As of today, though, bowing to pressure from a regulatory panel at the European Union, Microsoft has pledged it will lead the charge, and only hold onto your user data-IP address, text typed into search fields, etc.-for six months. Now it's up to Google and Yahoo to follow suit. (And since Bing only accounts for only a sliver of the searches currently being performed, their move is pretty symbolic.)What do you think it a fair amount of time? How do you feel about companies collecting and using information they gather about you every time you Google (or Bing, or Yahoo) something?