Good thread of answers above; I'll add a couple different ideas. I think it is good to ask the question why, and you should always trust your instincts and ingore or block anyone who acts inappropriately or who you aren't ready or willing to make a connection with. Having said that - there could be a hundred good reasons the person might have reached out, and an equal number of less than interesting ones, and yes, a few sinister...if the person isn't interesting to you, ignore it. Or if you want to know, ask them what their reasons

I've had friend requests from friends of friends just because of a great threaded conversation that sparked a dialogue or showed common interests. Some of those people, for me, have since become good FB friends who enrich my life with their posts, have turned me on to great resources. One in particular, who lives very far away, has become a regular writing partner and an inspiration. I've also had to

FB is evolving, and it's very quirky, and amazing. We are all figuring out how to use it. I say again, it's important to ask these questions, but don't throw out the baby, in the first bath anyway ; ).