Growth in internet advertising spend could slow in 2007, according to predictions from the US.

Trend analysis aggregator eMarketer suggests online advertising will grow from $16.4bn in 2006 to $19.5bn this year.

“This is 19% more than total spending in 2006,” the agency reported last night. “This rate of growth is sharply down from the 30% or more that has been the norm for several years.

“However, even this reduced level of year-on-year growth would be considered spectacular for most industries.”

eMarketer said worldwide advertising spend on social networks will more than double to $1bn this year. Its figures are based on data from the Interactive Advertising Bureau and PricewaterhouseCoopers.

The Internet Advertising Bureau in the UK says online advertising will have a “momentous” year. It reported that 2006 saw web ad spend grow to a projected 12% of media share, worth £2bn.