The software provides additional functionality to Microsoft's Instant messaging client, Windows Live Messenger, by adding its own controls to the main interface.

These controls affect Messenger's behaviour and appearance, often through additional dialog boxes.

It has become one of the most widely used add-ons for Microsoft's IM clients, citing over 62 million users as of February 2010.

community around the world develop skins and scripts for submission into the database of the website for the software.

[4] In Q1 of 2011 Paciullo officially declared he had left the company and that this chapter of his professional life was closed.

The petition, which had 401,683 signatures and was 10,137 pages long in total, was sent to Redmond on September 20, 2005[6] stating that Messenger Plus!

On September 23, 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!

[7] Recent versions of Windows Defender also stopped detecting the Messenger Plus!

Some software review websites criticized[8] 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.

3.60 was released (on September 27, 2005), the setup includes a separate sponsor license agreement in addition to a traditional EULA.

versions 4.84 and later no longer contain the sponsor program from Circle Development Ltd. Yuna Software currently uses more conventional methods.

Yuna Software also launched sites in 2010 affiliated with Messenger Plus!, including Plus!

versions caused sites such as McAfee SiteAdvisor to warn that the website www.msgpluslive.net was linked with adware Adware-Lop/Swizzor.

[10] However, SiteAdvisor has tested the current website www.msgplus.net and found downloads to be free of adware, spyware, and other potentially unwanted programs.

[19] which introduced 16 additional languages, video and voice transformation effects and ring tones.

for Windows Live Messenger/Skype sound archive, and also introduced a new default design for the add-on.

Notable features include:[23] Skype has announced its intention to discontinue the desktop API which is used by Messenger Plus!

Note that the date which this is to happen (originally in December 2013) is now unknown as Skype tries to come up with new methods to support a small subset of the Desktop API functionality.

There is currently no information available on the Yuna website that mentions the plans to handle the Desktop API being discontinued by Skype at some point in the future.

In the first version this year there is a "feature" that seem not to be mentioned anywhere: It sends an ad for Messenger plus as a chat message to random contacts.

In the second version this year (3.0.0.185) released in February 2014, this feature is mentioned and can now be turned off.