David Dalka raised an interesting point about Facebook's apparent policy change to open up public profiles for search engine indexing:

Facebook Spamming Your Identity To Drive Their Traffic

The other day I was highly surprised to learn that my Facebook profile was showing up in the top 10 for Google when you Google my name. In my opinion, turning on a feature like this without informing your users of the change to drive traffic using users’ identity to their social network via search engines is rather sleazy. After looking through their 89 zillion privacy options, I could not find a way to do it without excluding current community users which I did not want to do.

As Dalka explains above, he thinks Facebook should have been more clear about how public a public profile is, and give users explicit control over whether their profile can b e indexed by search engines.

Personally, I'm not bothered by this, but could see how some people may be. For example, people with relatively slim online histories are more likely to find their name's search results to include their Facebook profile than someone who's an active blogger and engaged in many online communities. Of course, a more active online personality is already more open about their personal lives due to the nature of their online behavior, so would probably not be bothered by one more search result about them popping up.

The biggest reason why I don't have an issue with this is the content on Facebook is within the control of each user. Whether it's indexed or not, the content contained within your own profile page is content you put their yourself. Put that together with the privacy settings you chose when setting up your account, and there really is no justification for shock here.

It looks like the profile indexing change is still relatively new since Facebook, as of this writing, has a mere 276,000 pages indexed in Google. Compare that to MySpace.com's 19,600,000.

Leveraging the search rankings of individual user's names is an incredibly powerful way to build the network. People Googling friends and happening upon Facebook are surely great candidates for joining the service in order to view full profiles, message other users, and build out their own profiles.

Mashable's Peter Cashmore offers some insight in the comments on Dalka's blog explaining profiles from Facebook are ending up in Google's index:

Actually, it’s not all that bad - it’s been like this at least 6 months, and Google only indexes Facebook pages that are linked to from elsewhere (most commonly, when you post a Facebook badge somewhere like a blog). When not logged in to Facebook, nobody can view that page, and those that are logged in only see a photo and location.

My advice: If you post something to the web, do so under the assumption that search engines will find it, and that it will live forever.