Facebook – Disabling the “seen message” feature on Facebook when friends send me a message

First, Facebook as a whole is more valuable if it maximises user volumes. So they're never going to stop wanting you to add that new friend from some other address book.

Second, the Facebook experience is pretty lame if you have only a few Facebook friends. So creating a new link may be a marginal value gain for you, but it may help the other party get into the sweet spot and become a regular and committed user.

More speculatively, Facebook ads themselves seem (from what I get offered, anyway), pretty feeble, so maybe there's an element of Facebook improving your general perception of the right-hand column by sometimes not even showing you some horrible, mis-targeted ad and just doing self-promotion, not caring all that much whether you respond. In this case, you've responded indirectly by talking about Facebook, I'm making a mental note to see if I am getting that same treatment, and we're both even more bought into the idea that Facebook is an unassailable, valuable site in a way that Myspace and other toppled social media towers must not have been!

Yes, even if you have received a friend request from her, you may not be able to Send her a message depending on her privacy settings.

What you can do here is accept her friend request; then place her under the list called, "Restricted" and then send her a message. Later you can remove her from your friend list.

Or, if you are sure that you do not know her (or anybody with that Nigerian Name); you can cancel her friend request.