Stephen Arnold at Beyond Search gave an excellent presentation at the Special Libraries Association annual meeting in New Orleans on real-time search. He liked Collecta too, a real-time search tool I cover in the book.
Two other sites he mentioned were Booshaka and OpenFacebookSearch.com. Both use the Facebook application programming interface (API) to send a search query from the Web into Facebook and to retrieve matching results. This allows you to search Facebook profiles without having to go to the Facebook site, and it means you do not have to have an account on Facebook either.
Neither site will return private information, since the Facebook API controls what is made available, and it is likely to adhere to whatever privacy rules are currently in place. I tried a number of search queries at these sites and the results appeared to be about the same. One feature I like about Booshaka’s site is that you can save your search query as an RSS feed, so that you can continue to monitor keyword activity on Facebook without returning to the site. Both sites enable you to create a Web-based widget, but this is not very relevant from a research standpoint.