The email announcing the renewed agreement between Microsoft and Yahoo! for search advertising included the fact that Bing has garnered more than 20% of the desktop search market, so I decided to chart a year's worth of data from comScore.
| Mar-14 | Apr-14 | May-14 | Jun-14 | Jul-14 | Aug-14 | Sep-14 | Oct-14 | Nov-14 | Dec-14 | Jan-15 | Feb-15 | Mar-15 | |
| 67.5% | 67.6% | 67.6% | 67.6% | 67.4% | 67.3% | 67.3% | 67.0% | 67.0% | 65.4% | 64.4% | 64.5% | 64.4% | |
| Microsoft | 18.6% | 18.7% | 18.8% | 19.2% | 19.3% | 19.4% | 19.4% | 19.5% | 19.6% | 19.7% | 19.7% | 19.8% | 20.1% |
| Yahoo | 10.1% | 10.0% | 10.0% | 9.8% | 10.0% | 10.0% | 10.0% | 10.3% | 10.2% | 11.8% | 13.0% | 12.8% | 12.7% |
| Ask | 2.5% | 2.4% | 2.3% | 2.1% | 2.0% | 2.0% | 2.0% | 1.9% | 2.0% | 2.0% | 1.8% | 1.8% | 1.8% |
| AOL | 1.3% | 1.3% | 1.3% | 1.3% | 1.3% | 1.3% | 1.3% | 1.2% | 1.3% | 1.2% | 1.1% | 1.1% | 1.1% |
Ask and AOL are likely to continue downward. Google's share of desktop search appears to be eroding, while both Yahoo! and Bing have both shown incremental growth.
(img src)