1. Definition Definition IM falls under the umbrella term online chat , as it is a real-time text-based networked communication system, but is distinct in that it is based on clients that facilitate connections between specified known users (often using "Buddy List", "Friend List" or "Contact List"), whereas online 'chat' also includes web-based applications that allow communication between (often anonymous) users in a multi-user environment.

9. User base October 2006 1 million total Meebo September 2006 1 million active (daily) Mail.ru Agent June 2007 1 million total IMVU unknown iChat December 2009 40 million total (licensed, entitled users in enterprises) IBM Lotus Sametime May 2009 Over 6 million active (majority in Poland) Gadu-Gadu mobile and PC Gizmo5 October 2006, including 4 million mobile users 35 million total eBuddy January 2006 >100 million total September 2006 53 million active AIM Date/source User count Service

10. Facebook statistics Claimed 400 million users Facebook unknown users. Chat within Gmail, iGoogle, and orkut, All on the web, PC and Mac Google Talk 17 Jan 2008 248 million active registered Yahoo global users (refers to ALL Yahoo users not Instant Messaging users) Yahoo! Messenger May 2010 16 million total Xfire June 2009 330 million active Windows Live Messenger (previously MSN Messenger ) December 2008 >550,000 VZOchat 29 Oct 2009 990 million total registered accounts. (majority in China) 29 Oct 2009 440 million active accounts (includes users with multiple accounts). (majority in China) 29 Oct 2009 61.3 million peak online (majority in China) Tencent QQ April 2008 309 million total October 2009 19 million peak online Skype February 2007. Note that these users are part of the IRC user base, messaging user base consists of a few hundred users 1 million active (daily) (majority in Brazil) PSYC August 2006 3.3 million unique visitors per month Paltalk