| Service | User count | Date/source |
|---|
| AIM | 53 million active | September 2006 |
| >100 million total | January 2006 |
| eBuddy | 35 million total | October 2006, including 4 million mobile users |
| Gadu-Gadu | 6 million active (majority inPoland) | June 2008 |
| IBM Lotus Sametime | 17 million total (private, in enterprises) | November 2007 |
| ICQ | 15 million active | July 2006 |
| IMVU | 1 million total | June 2007 |
| Jabber | 40-50 million total | January 2007, based on calculations of Jabber Inc |
| 90 million total | Based on calculations of Process-One: Process-One uses ejabberd as Jabber server software. If it is assumed that ejabberd has a 40% market share amongst public and private open source server deployments, there are 50 million users using open source servers. With Jabber Inc's numbers, this adds up to the 90 million number stated here. |
| Mail.ru Agent | 1 million active (daily) | September 2006 |
| Meebo | 1 million total | October 2006 |
| MXit | 11 million total (9 million in South Africa) | 29 January 2009. |
| Paltalk | 3.3 million unique visitors per month | August 2006 |
| PSYC | 1 million active (daily) (majority inBrazil) | February 2007. Note that these users are part of the IRC user base, messaging user base consists of a few hundred users |
| Skype | 16 million peak online | February 2009 |
| 309 million total | April 2008 |
| Tencent QQ | 40.3 million peak online (majority in China) | [14 May 2008] [12] |
| 317.9 million "active" (majority inChina) | [14 May 2008] [12] |
| 783 million total accounts "active" (majority in China) | [14 May 2008] [12] |
| VZOchat | >550,000 | December 2008 |
| Windows Live Messenger(Previously MSN Messenger) | 300 million active worldwide | [1] |
| Xfire | 11.5 million total | October 2008 |
| Yahoo! Messenger | 248 million active registered Yahoo global users | 17 Jan 2008 |
