Q: How do you know when someone blocks you in Facebook?
A: When you see your friends responding to his comment while you don't see any of his comments showing up.
Q: What kinda jerk would block people in Facebook?
A: I have no idea...
A: Perhaps he couldn't stand to share the "airtime" with you, even if it's just commenting on friend's status in Facebook. He just couldn't stand to see your name and picture (perhaps the display picture is too happy).
After more than 2 years, what is the problem with him? Perhaps somebody should teach him what is "forgive and forget".
(You know whom I'm talking about.)