The news could have turned against the search giant.

Then last Thursday Google pulled off a PR spectacular by signing up nearly every other significant social network other than Facebook to its OpenSocialpartnership.

OpenSocial will allow developers of third-party software applications, known as "widgets", to write a programme just once and have it ready for use on a variety of social networks including MySpace, Bebo, LinkedIn, Friendster and Google's own Orkut . . . which while popular in Brazil and India has been unsuccessful elsewhere. Oracle as well as Salesforce. comwere also founder partners.

Facebook, conspicuous by its absence from the industry alliance, was initially thought to have snubbed the effort, banking on its own independent success. But it soon emerged that Facebook had not been briefed on the project, making the outcome seem like a bit of PR skulduggery heretofore not thought to have been in Google's vocabulary.

Web users have flocked to social-networking sites to find old friends, socialise with colleagues, listen to music and play games. Spending by advertisers on the sites may almost triple to $3.63bn globally by 2011, according to EMarketer.

Facebook, based in Palo Alto, California, and MySpace will account for three-quarters of the market's $900m in ad revenue this year, the New York-based research firm said.

MySpace attracted 105.7 million users worldwide in August, compared with 69.3 million for Facebook, according to US-based researcher ComScore.

The lesson: Google may have "don't be evil" as its motto, but you might want to think twice before making them angry.

(additional reporting Bloomberg)