<right Google is really growing into its gorillahood. A quick calculation (via HipMojo), based on the latest figures from the Interactive Advertising Bureau, shows that in the first half of 2007 Google commanded a 40 percent market share of all online advertising in the U.S. (Okay, I’m rounding up. It was really 39.8 percent). But that compares to a 34.6 percent share in the first half of 2006, based on IAB data for that period. Here’s the math:

$3.98 billion (Google’s U.S. revenues in the first half of 2007)/$9.99 billion (IAB’s estimate of total U.S. online ad revenue in 1H07) = 39.8 percent.

For the first half of 2006 the numbers are:

$2.732 billion (Google’s U.S. revenues in 1H06)/ $7.9 billion (IAB’s estimate of U.S. online ad revenues in 1H06) = 34.6 percent.

Update: As one commenter points out below, this means Google is out-pacing the growth of online advertising by a wide margin. Total online advertising revenues grew 26.5 percent year-over-year, while Google’s ad revenues grew 45.7 percent.

All numbers come from Google earnings releases and IAB.