Having someone to talk to and share feelings and interests with can always be nice, whether it's online or offline. So while I would admit I don't necessarily "know" people online very well, if we talk to each other, and that talking makes me happy, I would never say "I can't call you a friend". These days I talk online to a mix of real life friends who I don't see much, people I have met and a couple of people I've never met. Friends in general are good to have.