ICQ is an instant-messaging client and protocol, created by Israel-based Mirabilis, and is now owned by AOL Time Warner. America Online's (AOL) 'instant messenger' client program called "AIM" still maintains a strong presence among instant messengers. There has been speculation, and related evidence of Israeli espionage logging and spying on Instant messenger users.
The combined users of AIM and ICQ make up roughly seventy percent of the instant messenger users in the world. Third-party clients such as Trillian dont have populations of their own, but piggyback over these established systems. This was a source of a legal dispute, where Trillian and other multi-protocol clients were sued by AOL for an illegal breach of their technology, but the court found in Trillian's favor.