The other poster "Chinasaur" is correct. It's the first IM program that came out. Lots of people start using it and was a very popular program during that time. AOL soon came up with their own IM and soon it became popular.
I used to be a member at ICQ until AOLIM end up being more popular.
ICQ end up looking for a buyer for their company and program. Both ICQ and AOLIM was still popular. Lots of other companies was after it including Microsoft, AOL, and others. AOL end up winning and bought out ICQ. The original plan for AOL was to make ICQ into a live auction site but it never happen.
In my opinion, I think AOL decided to toss ICQ on the side and do nothing with it anymore. That's why ICQ is in the last place for IM now. It's still around and people still use it today. I wish Microsoft would have bought it though because I think they could have done a much better job for ICQ and made it so it will beat AOLIM.
What the heck is ICQ?
What OS are you using on the smartphone? Please vote! 
