>If you don't mean a Google search, I'm not sure what you could mean.

If you're considering buying a motorcycle and have a friend (or a group of friends) that own(s) a motorcylce, are you more likely to ask that friend (or that group) the pros/cons of owning a motorcycle and for their recommendations or are you far more likely to use "nature language sentences" in Google to illicit that information (e.g.: "I'm thinking of buying a motorcycle")?

I'm going to posit that the former occurs far more frequently than the latter and that this is the potential "untapped market" for targeted advertising that a "private social network" would be after.