Online user groups have seized power from vendors and are increasingly calling all the shots.

In recent years the online user community has rapidly gained power, representing a turbulent arena for vendors, according to Gartner research director Steve Prentice.

He warned vendors they need to rethink how they exploit users for marketing purposes.

"These communities provide a strange and implicit trust between anonymous users," Prentice added.

While vendors can use these communities as a support centre, Prentice warned they risk savage retaliation and bad publicity if marketing is surreptitiously introduced.

"These communities are very strange entities as users will go out of their way to help someone they have never seen before and this advice is trusted without question - and in most cases, rightly so," Prentice said, adding that users aim to present accurate information in order to build online reputations.

"While we are seeing businesses successfully leverage these user groups as support centers for their products, I know of some scalps that the groups have claimed as a result of sly sales pitches slipped into a forum."

According to Prentice, the groups are an invaluable access point for customers and should be used to refine business strategy and marketing.

It also provides opportunities, he said, for swift-moving vendors.

System Administrators Guild of Australia (SAGE-AU) executive member Donna Ashelford said for many users such forums are first port-of-call.

"User groups are the primary support point for most users, but this depends on which group is being accessed," Ashelford said.

"Many businesses host forums and user groups, but others, like SAGE-AU, are member-only so they don't have [public] access.

"The quality and accuracy of information depends on the group and the topic, but you'll find the most accurate discussions are those that users can edit, such as wikis."

She agreed that vendors put themselves at risk if they attempt to deploy sales pitches.

"It again depends on the environment of discussion as to how tight the user culture will be and therefore whether users will launch a backlash," Ashelford said.

"Vendors simply need to know there is a time and a place for campaigning."