So I noticed this last night when I was Facebook friended by one of my kids' friends. He's a nice kid but I didn't want to have that kind of relationship with him so I was ready to hit ignore. Then I noticed the "Ignore" option has been replaced by a "Not now" choice. It actually felt like a good option. I like the kid, I don't want to be rude, and by hitting "not now", I could feel like I was just procrastinating instead of rejecting.
But the implications here are kind of huge: you can't immediately refuse a friend request any more. You can just postpone accepting it.
It's a new feature on Facebook and when you go the "not now" route, it subscribes the requesting/delayed suitor to your public updates so they still feel like they're following you (obviously they don't see anything if you've set the privacy settings on your updates to Friends Only but that is still not the default). Tech Crunch writes about it:
With the Not Now button, Facebook took what was a one-step rejection and made it at least two steps -- and that's only if you want to truly block somebody (after you click the Not Now button, they ask "Don't know XXXX XXXX?" and if you click that, it will block them from making any further friend requests). If you just want to deny a person's request without blocking them, you have to go to the Requests page -- the limbo area that Facebook sends the Not Now people to. This area isn't particularly easy to find; it's buried in the Friends -> Find Friends area. In other words, it's now quite a few steps simply to reject a person's friend request as you previously could.