Most Helpful Guy
because guys regret stuff like this.. so after they realize they fucked up they start stalking you on FB lol
Most Helpful Girl
When you block someone on facebook, it means that you can't even check the blocked person's page anymore. Maybe he got curious and unblocked you in order to check out your profile. And according to facebook's rules, you can't keep blocking and unblocking people whenever you want. I think you have to wait 24-48 hours before you can block that person again or something. So check back in a couple of days and see if he has blocked you again. If he has, it most likely means he just wanted to snoop around on your profile.
If not, maybe he's over it and thought blocking you was unnecessary. Or, maybe he's planning on contacting you soon, or hoping you'll contact him.
For me, personally, I wouldn't go around blocking and then unblocking a guy I "used" to have feelings for unless I was going back and forth with my feelings. Like if I've moved on, he stays blocked. If I haven't, I could see myself unblocking him just to check on him. But then again that's just me, and I don't block people unless they're harassing me or something. So I wouldn't block an ex just because I've moved on.