I think online friends can be great and especially with people who like to open up and be completely honest and that is a lot easier to do from behind a keyboard or texting than it is to do in person for a lot of us.
That's not to say that I don't talk to people in person and state my opinion about things and take part in friendly conversation. In fact I do that as well but, it's much easier online because you are not concerned about your body language or facial expressions or distracted by the other persons expressions and stuff so, I feel like online friendships are a good way to get to know someone at a slower pace and get an idea of what they may be like in person so, you will know what to expect if you should ever meet them.
I am also effected very emotionally by online friends and when I know that they hurt over something I hurt as well.