It means nothing. Absolutely nothing.
It means that he doesn't live on Facebook, like most other adults I know. I log on, check and reply to messages, and log off pretty much immediately. My average Facebook visit is under five minutes.
It means he is in the toilet wanking his wanking over pics he found of you on the web.
he is fooling with you. & does not mean what he says
he's probably shy or afraid that you may not like it so he runs away before you can slap him online :P