What do you mean " date" ? You can't date someone you can't see,hear, or touch. You can't date letters on a page. Do you mean form an acquittance, informal friendship? Be careful, never give out any personal information, you can never be sure who you are talking with. " Date " people you know, people you can see on a regular basis.
Of course you can, but preferably you shouldn't just for safety reasons, and to keep you away from any trouble. I mean you never know if there dating someone else at the same time, and just want you for inappropriate purposes only because they seem to not get it. Or if they lied about who they are,...their so much cons about dating someone online, than pros so in my opinion I wouldn't but then that's just me :)