So much for social network advertising. eMarketer has revised its earlier forecast for 2011 down to £2.2 billion ($4.32 billion) $3.79 billion), citing “today’s economy, combined with the fact that social networks are still trying to develop successful ad models”.

Growing social media audiences, plus the potential to mine profile data for targeted advertising, had offered great hope - and plenty of hype - for this sector. But Facebook’s user biteback at its Beacon proposal, for example, seemed to underscore a scepticism about such advanced practices at least. eMarketer analyst Debra Aho Williamson: “Social network sites are still trying to figure out what sort of advertising works. Tapping into consumers’ conversations and spreading brand awareness virally has proven more challenging than companies originally thought.”

The go-go growth is behind us. By the time social net ad spend hits 2011, it will be showing its slowest annual increases. The biggest boom came in 2007, when spend grew 135 155 percent. In 2008, social net ad spend is forecast to grow to £1.03 billion ($2.02 billion) $2.015 billion - but that’s only a 68 65 percent year-on-year growth. Up to 2011, the growth is forecast to be a shrinking 35 32 percent, 22 percent and 20 17 percent respectively. eMarketer aggregates primary research from peer analyst groups.