Facebook recently made it so that when someone comments on one of your posts, the friends of that commenter will see that comment, and your post, even if they are not friends with you. And, they can comment on that post of yours, even though they are not friends with you*. Now, commenting on your post seems a rather friendly thing to do, so you may be tempted to send these people a friend request. After all, they came and posted on your timeline. And you have at least one friend (probably more) in common. Sending a friend request seems the neighbourly thing to do with someone who writes on your wall, and with whom you share common friends. (*This depends on your Facebook settings, but if the post is set to ‘public’, this will be the case.)

But uh, uh, uh…don’t touch that ‘friend request’!

Because even though they came to you first, and even though they posted on your wall, and even though you may have dozens of friends in common – if a few people like this decline your friend request, Facebook will spank you. Yes, Facebook will block you from sending friend requests because of this.

And that’s not all.

Facebook will simultaneously block you from messaging anyone with whom you are not friends.

This means that when one of those people to whom you sent the friend request sends you a message saying “Hi, got your friend request, how do we know each other?” you won’t be able to answer them! Which in turn will make them even more inclined to decline your friend request.

And it gets even worse.

Look at this picture again:

Do you see how it’s not at all obvious that if you add a comment it will go to “No Idea Who This Is”‘s wall? So people who are friends of “Actual Facebook Friend” will think they are posting on Actual Facebook Friend’s wall; in many cases they will have no idea that they are posting on your wall – they think they are posting on their friend’s wall.

Which brings us back to the main point – even though they have commented on your wall, they will have no idea that they have commented on your wall, and will have no idea who you are.

So, don’t get caught in this Facebook trap.