Early instant messaging programs were primarily real-time text, where characters appeared as they were typed. Modern implementations of real-time text also exist in instant messengers, such as AOL's Real-Time IM 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, which they called "On-Line Messages" (or OLM for short), and later "Flash Mail." (Quantum Link later became America Online and made AOL Instant Messenger (AIM, discussed later).This includes the Unix "talk" command line program, which was popular in the 1980s and early 1990s. While the Quantum Link client software 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.Instant messages are often logged in a local message history, making it similar to the persistent nature of emails.Though the term dates from the 1990s, instant messaging predates the Internet, first appearing on multi-user operating systems like Compatible Time-Sharing System (CTSS) and Multiplexed Information and Computing Service (Multics) in the mid-1960s.IBM Lotus Sametime's November 2007 release added IBM Lotus Sametime Gateway support for XMPP.As of 2010, social networking providers often offer IM abilities.Instant messaging systems tend to facilitate connections between specified known users (often using a contact list also known as a "buddy list" or "friend list").
In 1998, IBM released IBM Lotus Sametime, a product based on technology acquired when IBM bought Haifa-based Ubique and Lexington-based Databeam.In many cases, instant messaging includes added features which can make it even more popular.For example, users may see each other via webcams, or talk directly for free over the Internet using a microphone and headphones or loudspeakers.Short messages are typically transmitted between two parties, when each user chooses to complete a thought and select "send".Some IM applications can use push technology to provide real-time text, which transmits messages character by character, as they are composed.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" meaning they charged an extra per-minute fee on top of the monthly Q-Link access costs.By 2010, instant messaging over the Web was already in sharp decline, Instant messaging is a set of communication technologies used for text-based communication between two or more participants over the Internet or other types of networks. Of importance is that online chat and instant messaging differ from other technologies such as email due to the perceived quasi-synchrony of the communications by the users.Some systems permit messages to be sent to users not then 'logged on' (offline messages), thus removing some differences between IM and email (often done by sending the message to the associated email account).More advanced instant messaging can add file transfer, clickable hyperlinks, Voice over IP, or video chat.Non-IM types of chat include multicast transmission, usually referred to as "chat rooms", where participants might be anonymous or might be previously known to each other (for example collaborators on a project that is using chat to facilitate communication).