internet - Why so many chat-systems?

This morning an email from my friend and colleague Maria Trombly, a pretty dynamic lady, although she has a heavily outdated website. Since I went online, I have become rather addicted to the new way of communicating, first by experimenting with ICQ (now largely dumped, because others are better), then expanded to MSN messenger (dabei233@hotmail.com), then added Yahoo messenger (tuinstranl@yahoo.com) as orginally their conference systems were pretty cool - although the quality sucks. Now, I'm mostly on Skype (fonstuinstra), but keep often the others running too. Hey, I do not want to miss out on anything.
Maria want to talk to me urgently on AIM, the only bloody chatting system I'm not using. And, I'm not going to register for this, Maria. Time for some cooperation, just like using the phone systems: even though it concerns different operators, mostly you can still call each other.