Are you interested in him romantically, or to just be friends?
There is a certain Facebook ettiquet about these things. Not forcing the issue is an extremely good idea. Don't comment on every post he makes, or even click "like". In Facebook land, that is considered stalking. Comment on one thing, then give it a rest for a bit.
I learned the hard way. I'm a man, and my friend was a girl. She felt I was stalking her and seeking to be romantically involved. She sent me nasty e-mail telling me never to contact her ever again in any way. yikes.