umnik700's answer is fairly dead-on if you're not considering issues related to authentication or who gets to see what. Consider the difference between the profiles you see when you're logged into Facebook versus those same profiles' publicly facing, searchable counterparts. Even MySpace, with a lot less consideration for search engine privacy, has viewability that is dependent on your relationship to the other person, defaulting, for private profiles, to "This profile has been set to private by the user" or something to that extent.
If you're looking to suddenly scale out a social tool where individuals are eliciting their personal information, I would suggest umnik700's answer (dynamically generate the content, but not the URLs, for public versions of the profile) with the following corollary: you need to be able to support privacy preferences varying from extremely strict to completely open, and default to a version that at least errs on the stricter, more private version of the profile. If you're just now pushing out searchable personal content when there never was any way to find it outside the site before, it's important not to abuse information given under different pretenses.
I know this probably requires maybe more scalability and added functionality than you were hoping this project would take, but to do otherwise could be most likely taken as a violation of your user base's tacit trust. Anyway, the best strategy to do this will probably require you to lean on your database more anyway, so it might be time to rework it a bit--including adding some privacy preferences.