I am not sure how many people are still using ICQ out there but from what I have heard it is still pretty popular internationally. RIM officially announced on their Knowledge Base that as of December 4th, 2010 they will no longer allow users to download the ICQ for BlackBerry app and any current users will find the app no longer works. If you try using the app it will just show:
Version 2.5+: Please visit: http://www.blackberry.com/btsc/KB24935
Older Versions: Connection Error (65): Problem receiving data from the server.
RIM is simply recommending that you delete the app and if you still need ICQ access they are pointing you to App World to download it. I guess the population of ICQ for BlackBerry users was not big enough for RIM to justify continued development of the application. Hopefully they will replace it with Facebook chat soon since quite a few users are begging for that. Better yet RIM could just release a straight up Jabber client…