Personally I think a "friendship" can be formed certainly, I love the friends I have met online from around the world.

As for a Romantic online relationship, well I think if there are plans to meet this person irl then sure ldr online can work. But if there is no way to actually met and physically touch that other person and your only means of communications is talk, text and skype. I can't picture that working long term, Humans need for touch is something that eventually is a must have for *most* people.

Every situation is different of course. But for me this is how I feel.