I tend to stick to one main friendship, but then in a situation like you described, op, sometimes I feel like I am too dependent on this one person and too much impacted by their quirks. Lately I have tried to build a few more relationships so if one person isn’t responding or is frustrating me with their behavior, I can contact the other person/people. But then it gets more complicated keeping up .
One thing I have found most difficult about online friendships that some people have so many that they really aren’t as attentive to me,. That is,they are using the quantity rather than quality approach with friendships.I know one person who doesn’t even answer all his emails, tho he works such long hours overseas in Iraq where he has to fight the isolation that sometimes I feel OK about this.