Although probably not quite as inflammatory as the current position of RIM Kik Messenger, Research In Motion has decided that they will not work on ICQ for BlackBerry more and to rely on 4 December, they disable the instant messaging service. RIM is not alone, either - ICQ dropped Nimbuzz a few weeks ago too.
The main difference between the ICQ for BlackBerry versus Android or iPhone application is that RIM is one who makes the RIM APP uses the same architecture for all major instant messaging clients, but I guess it is just old and unpopular enough not to be worth.
I remember permanently from ICQ well before MSN and Google Talk, and even after the two others came, it was still kind of cool because you could see what people would type as they typed, like Wave of Google.De anyway, one can only hope that ICQ takes the chore of developing their own shows to keep their users happy little BlackBerry client.
If you are a passionate user inveterate, you can find more info about the closure to this knowledge base article.
