The instant messaging software enables you to set up a list of contacts that also use the program. Once you set up this list, you can see who is online at a particular moment. If the person you want to talk to is online, you can begin a text, voice, or video conversation with them quickly and easily. If they are not online, you can still send a text message that they will receive when they login or leave them a voicemail.
With more than 400 million instant messages sent and received every day, ICQ has been known to the online community as a messaging service, but today, 10 years after the first ICQ instant messaging service was launched, ICQ has become much more than just that.
Skype is a little piece of software that allows you make calls from your computer. Talk for as long as you like without worrying about the cost or the distance.
Jabber is best known as "the Linux of instant messaging", an open, secure, ad-free alternative to consumer IM services. Jabber enables any two people on the Internet to exchange messages, presence, and other structured information in close to real time.