As part of an initiative to promote Windows Live Messenger 8.1, Microsoft will give away a percentage of the advertising revenue it gains from participating users, according to an announcement made Thursday on the software vendor's Channel 10 product news Web site.

U.S. users of WLM can choose among nine nonprofit groups: the American Red Cross, the Boys & Girls Clubs of America, the National AIDS Fund, the National Multiple Sclerosis Society, Ninemillion.org, the Sierra Club, StopGlobalWarming.org, the Susan G. Komen for the Cure organization and the U.S. Fund for UNICEF.

In a document explaining the "i'm Initiative" that was posted on Microsoft's Web site, the company said the amount that will be donated to charities per user "is small." But Microsoft pledged to donate at least $100,000 to each charity in the first year of the program. It added that there is no scheduled end date for the program and no cap on the amount of money that will be donated.

Users must use WLM 8.1 or subsequent releases of the IM software, which formerly was known as MSN Messenger. Version 8.1 was released Jan. 30, along with Windows Vista and Office 2007. The new release is Vista-compatible and can be used to communicate with users of Yahoo Inc.'s instant messaging software.