Two out of three online measurement firms agree: Bing lost ground in December. Experian Hitwise and Nielsen saw Bing’s search share decrease from November, while comScore saw it grow.

comScore saw Bing grow 4% from 10.3% to 10.7% (and Yahoo, Ask & the rest lost some). Hitwise, however, reported that Bing saw a 4% decrease in December (0.42 percentage points, coming in at 8.92%), as did Yahoo (0.56 percentage points, now 14.83%) and Ask (0.11 percentage points, now 2.54%). Google, naturally, grew 1% (0.68 percentage points, 72.25%). Nielsen reported an 8% drop in Bing’s share (0.8 percentage points, 9.9%), while Yahoo saw a 6% drop (0.9 percentage points, 14.4%).

Comparing the data to May (the last month of Microsoft/Live search before Bing’s launch) yields somewhat different results. Nielsen shows that Bing gained 0.5 percentage points by December, while Hitwise shows they’ve gained 3.28 percentage points. comScore says they’re up by 2.7 percentage points over that period.

However, all the measurement firms agree that Google was up and Yahoo (and Ask) slightly down in December. If Bing’s success is coming at Yahoo’s expense, will this bode well for their deal?

We saw lots of early reports that Bing was growing its market share, but after six months, are the results as dramatic as you expected?

via