The latest set of online ad revenue numbers from the Interactive Advertising Bureau offers further confirmation that while growth remains healthy, it is nevertheless slowing down consistently. The survey, which was conducted with PricewaterhouseCoopers, includes data on internet ad revenues from web sites, commercial online services, free e-mail providers, and all other companies selling online advertising. Here’s the breakdown:

-- Online advertising revenues in the U.S. for the first six months of 2007 were nearly $10 billion, a gain of 26.6 percent over H106. In comparison, the IAB said last year that H106 ad spend was about $7.9 billion, 37 percent higher than the same period in 2005.

-- As for Q2, online ad spending came in at $5.1 billion, a 25.4 percent increase over the same period last year. In Q206, internet ad revenues were $4.1 billion, which was 36 percent greater than Q205.

-- Looking at the separate categories for H107 versus last year, the changes in spending were fairly small for most categories. Search advertising was up 41 percent to $4 million (versus H106’s 40 percent rise over H105’s $3.1 million), while classifieds were up 17 percent for the first six months of the year to $1.6 million (the same category in 2006 rose 20 percent over H105 to $1.5 million).

-- In terms of pricing models, performance deals took a slight lead over CPMs during the first half of the year. Performance deals amounted to 50 percent in H107 taking in $4.9 million; in H105, those deals amounted to 47 percent of the market, taking in $3.7 million. CPMs for H107 were $4.4 million, an increase of 45 percent; CPM’s in H106 were 48 percent higher over the 2005 period to $3.7 million. Release

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