In 2000, an open source application and open standards -based protocol called Jabber was launched

In the latter half of the 1980s and into the early 1990s, the Quantum Link online service for Commodore 64 computers offered user-to-user messages between concurrently connected customers, [citation needed] which they called “On-Line Messages” (or OLM for short), and later “FlashMail.” [citation needed] (Quantum Link later became America Online [citation needed] and made AOL Instant Messenger (AIM), discussed later). While the Quantum Link service ran on a Commodore 64 , using only the Commodore’s PETSCII text-graphics, the screen was visually divided into sections and OLMs would appear as a yellow bar saying “Message From:” and the name of the sender along with the message across the top of whatever the user was already doing, and presented a list of options for responding. As such, it could be considered a type of graphical user interface (GUI), albeit much more primitive than the later Unix , Windows and Macintosh based GUI IM software. OLMs were what Q-Link called “Plus Services” [citation needed] meaning they charged an extra per-minute fee on top of the monthly Q-Link access costs.

Modern, Internet-wide, GUI-based messaging clients as they are known today, began to take off in the mid 1990s [citation needed] with PowWow , ICQ , and AOL Instant Messenger . Similar functionality was offered by CU-SeeMe in 1992; though primarily an audio/video chat link, users could also send textual messages to each other. AOL later acquired Mirabilis , the authors of ICQ; [citation needed] a few years later ICQ (now owned by AOL) was awarded two patents [citation needed] for instant messaging by the U.S. patent office. Meanwhile, other companies developed their own software; [citation needed] ( Excite , MSN , Ubique , and Yahoo ), each with its own proprietary protocol and client ; [citation needed] users therefore had to run multiple client applications if they wished to use more than one of these networks.