Tim Bradshaw at FT.com reports (sub. required) that Sir Martin Sorrell, head of WPP, the world's largest marketing and communications group, has doubts about mixing advertising with social networks, such as Facebook.

Sir Martin warned on Tuesday that social media sites are ”less commercial phenomena, they are more personal phenomena”, more similar to ”writing letters to our mothers” than watching television.

”Invading these [social] media with commercial messages might not be the right thing,” Sir Martin told delegates at the Financial Times Digital Media and Broadcasting Conference in central London.

He also said he was concerned about Facebook's record on privacy.

...more than once, Facebook has ”screwed up royally” on privacy by trying to introduce intrusive advertising systems such as its aborted Beacon service.

”My view is that [privacy] is still a social norm,” Sir Martin said. ”People are still concerned about it and the invasion of it.”

He's worried that Facebook's misadventures on privacy would create new government regulations affecting everyone.

Foremski's Take: Sir Martin Sorrell's concerns about advertising on social networks and the comparison with personal messages to mom, seem unusual. Advertising on Gmail has been around for a long time, and advertising on Facebook has also been a part of that site for a long while.

However, advertising on Facebook has not been very successful and ad rates are low. If Mr Sorrell is trying to get corporations to increase their online ad budgets he might prefer them to avoid the low cost and thus low margins WPP would earn on Facebook ads, and steer them to larger, more creative advertising campaigns on traditional media sites.