One week after it added the creator of a Windows Messenger add-on to its list of MVPs (Most Valued Professionals), Microsoft has revoked the award after critics pointed out that the program is used to distribute adware.

Last week Microsoft named Cyril Paciullo, the creator of Messenger Plus and Messenger Plus Live, to its list of MVPs. The award recognises people with expertise in Microsoft products who make significant contributions to other users, often in the form of technical advice.

Messenger Plus is a free program that adds some useful functions to Microsoft's IM (instant-messaging) software, such as the ability to stack several chat windows together and access them via tabs.

However, security experts pointed out last week that Paciullo's software is also used to distribute Lop, which they described as a nasty adware program. Other MVPs said his addition to the list made a mockery of the MVP scheme.

"The bottom line is that Microsoft is rewarding someone that has an active involvement with one of the most maligned names in PC hijacking," Christopher Boyd, a Microsoft Security MVP who's also director of malware research for FaceTime Security Labs, wrote in his blog last week.

On Friday Microsoft decided to take back the award.

"Cyril Paciullo was awarded with MVP status this year on the basis of his technical expertise and strong community contribution. However, his active MVP Award status was revoked as soon as the extent of the connection between his application and spyware was made apparent to the MVP programme," the company said in a statement.

Paciullo, who uses the nickname Patchou, couldn't be reached for comment. He acknowledges on his website that some anti-adware programs issue a warning for the 'sponsor program' that comes with Messenger Plus. But he says the sponsor program is not dangerous and that users have the option not to install it.

Microsoft said it conducts a rigorous selection process to find the most qualified people to become MVPs, and that it's committed to maintaining the integrity of the award. There are about 2,600 MVPs worldwide.