The add-on was first released in May 2001 under the name "The Messenger Plus! Extension" for MSN Messenger and Windows Messenger. It later changed its name to "Messenger Plus!" and then, for the release of the new Windows Live Messenger client, "Messenger Plus! Live" was chosen. It has become one of the most widely used add-ons for Microsoft's IM clients, citing over 340 million downloads as of December 2007.
Messenger Plus! Live 4.70, released on the 9th of August 2008, is the latest branch and contains many new features (such as skinning), visual improvements and bug fixes.
Currently, Messenger Plus! Live doesn't support the public beta of Windows Live Messenger 2009. However, Patchou has stated on the official forums that he has begun work upon a compatible version.
Version 4.50 added support for skinning Windows Live Messenger without the user having to physically edit the program's resource files.
A more complete list of features can be found here
Some software review websites criticized the user agreement, stating that the 'sponsorship agreement', which authorized the installation of the optional adware software, was misleading because it looked like a standard EULA, and was only available in English. Since Messenger Plus! 3.60 was released (on the 27th of September 2005), the setup includes a separate sponsor license agreement in addition to a traditional EULA. Both agreements have also been translated in several languages.
McAfee SiteAdvisor warns that the website http://www.msgpluslive.net/ is linked with adware Adware-Lop/Swizzor.
A separate adware uninstallation program is provided by Circle Development Ltd. which appears when users attempt to uninstall the sponsor program of Messenger Plus!.
The petition, which had 401,683 signatures and was 10,137 pages long in total, was sent to Redmond on September 20 2005 stating that Messenger Plus! should not be labeled as being a threat.
On the 23rd of September 2005, just 3 days after the petition was mailed to Redmond from Canada, Microsoft released new definitions for Windows Defender that fixed the false threat detection affecting the Messenger Plus! executable together with other detection improvements.
Recent versions of Windows Defender also stopped detecting the Messenger Plus! Live installer as being potentially dangerous.
To coincide with the newly branded Windows Live Messenger, new versions of Messenger Plus! are called Messenger Plus! Live. It has been completely rebuilt from the ground up and includes a totally new GUI design which blends more into the GUI of Windows Live Messenger.
The MSN Messenger compatible Messenger Plus! will no longer be supported. However, the last version of Messenger Plus! (version 3.63) will still be available for download on the official website here and is able to run along side Messenger Plus! Live.