Ichat is a discontinued instant messaging software application. It was part of what is known as collaborative software, which means it supports email, text, chat, online dating services, and social networks such as Facebook, Twitter, and Ichat and Skype. Ichat was developed in 2002, and it can be used on Mobile ME, Mac.com, AOL instant messenger, or Google Talk. It features video, screen sharing, and text messaging. It's videos and audio chat are based on the Session Initiation Protocol, which is not the same as what Skype uses. Skype is an application software which was developed in 2003. Users chat and make voice calls on the Internet. You can make calls, send instant messages, and video chat with other Skypers. Skype calls are free, but calls on mobile phones and landlines are not. Also, Skype uses an internet telephony network called the Skype protocol.