GUYS: what do you mean when you ignore a girl ON FACEBOOK?

He probably didn't expect you to be so 'friendly' after all it has been 8 years. Most guys don't warm up as much as girls do, I don't understand why he wouldn't respond to your wall post though, maybe he's wary of 'strangers', people he doesn't yet feel comfortable with. That's the awkward thing about facebook, you really have to get to know someone in person first. At least in my experiences.