A new report on the state of the search market has been released, and, in keeping with tradition, it represents good news for Google.  The search giant gained a significant amount of ground in September, according to comScore, although the real story might be Yahoo’s loss.

Yahoo’s market share fell from 17.4 percent to 16.7 percent on a month-over-month basis, which is rather a lot if you consider that 0.7 points count as four percent of 17.4 points.

Toss in the fact that the loss occurred as Yahoo was completing its arrangement with Microsoft, and Carol Bartz may have some explaining to do (especially if Yahoo’s third quarter earnings report doesn’t go well).

It’s not like Microsoft stole lots of users from its new partner, however, as Bing’s market share only rose from 11.1 percent to 11.2 percent between August and September.  To explain where everyone went, it’s instead necessary to return to the subject of Google’s small jump.

The search giant saw its market share increase from 65.4 percent to 66.1 percent on a month-over-month basis, bringing it near the two-thirds mark.  As always, that’ll translate to more money, and it could also signal that people like Google Instant.

Hat tip goes to Danny Sullivan and the analysts at UBS, who published comScore’s data before comScore itself could get around to putting out a press release.

UPDATE: Yahoo’s posted an explanation/rebuttal of sorts on the Yahoo Search Blog.