CompuServe (CompuServe Information Service, also known by its initialism CIS or later CSi) was an American online service, the first major commercial one in the world – described in 1994 as "the oldest of the Big Three information services (the others are Prodigy and America Online)."It dominated the industry during the 1980s and remained a major influence through the mid-1990s. At its maximum during the early 1990s, CIS was known for its online chat system, message forums for a variety of topics, extensive software libraries for most personal computers, and a series of popular online games, notably MegaWars III and Island of Kesmai. It was known also for its introduction of the GIF format for pictures and its system for exchanging GIF.In 1997, 17 years after H&R Block had acquired CIS, the parent company announced its desire to sell CIS. A complex deal was devised with WorldCom acting as a broker, resulting in CIS being sold to AOL. In 2015, Verizon acquired AOL, including its CompuServe division. In 2017, after Verizon completed its acquisition of Yahoo!, CompuServe became part of Verizon's newly formed subsidiary Oath Inc., which was then divested as the new Yahoo! company during 2021. Source: Wikipedia (en)