Smaller rivals like Jumptap and Millennial Media are also gaining, according to IDC
The pie chart at right is somewhat premature, given that it is IDC’s best guess — via
Bloomberg Businessweek
— of what the $500 million U.S. mobile advertising market will look three months from now.
But it’s an indication of how the winds have shifted. Apple (AAPL), which had 0% share of the market before it bought Quattro Wireless in January and launched iAd in June, will end the year at 21%, according to IDC.
Where did that share come from? Chiefly from Google (GOOG), Yahoo (YHOO), Microsoft (MSFT) and Nokia (NOK), according to the Businessweek piece.
IDC’s before-and-after numbers for the biggest losers below the fold.
| Dec. 2009 | Dec. 2010 | |
| 27% | 21% | |
| Yahoo | 12% | 9% |
| Microsoft | 10% | 7% |
| Nokia | 5% | 2% |
. . .
[Follow Philip Elmer-DeWitt on Twitter @philiped]