I think too many people are falling for the "keep in touch with friends" aspect. We used to do that via email, phone, etc. But to post part of your private life on the net and voluntarily offer such information for all to see is what's worrying.
That's why I am wondering if this has been really considered by all those using it before it becomes a household name (actually already has) before anyone really raises a flag and places some qulaifications on how that information is used. Remember when you click to use any application, you are asked for your consent to use your information. Is there anything in small printed text the the general public is missing?