ComScore today released its U.S. desktop search share report for January. Like in the previous report, Yahoo has again managed to eat into Google’s pie.

As you can see in the chart below, Yahoo gained 1.2 percentage points to hit 13 percent, while Google slipped 1.0 points to 64.4 percent. Microsoft’s Bing stayed flat:


For many months, ComScore’s reports show next to no movement for each search service (a difference of 0.1 points or 0.2 points one way or the other, if that). In December, Yahoo stole 1.6 percentage points from Google, and now in January it has grabbed another point.

Yahoo has thus directly taken 2.6 percent from Google in two months, according to ComScore, thanks to the five-year deal Yahoo struck with Mozilla on November 19 to become its default search engine in the U.S. Because Google was the default search engine of choice before, it also follows that the majority of the search share Yahoo is gaining, Google is losing.

The deal technically only went into effect on December 1, when Firefox 34 released with Yahoo as the default search engine in North America (Yandex also became the default for Russia, Belarus, and Kazakhstan). We predicted the January jump in our coverage last month:

As such, we may see the impact on the U.S. search market spill over into January numbers. Firefox users don’t update as quickly as those on Chrome (though they do update much faster than IE users). So we may see Yahoo’s search share increase further in January as more people update to the latest version of the browser.

The real test will be whether or not these gains last. Many may try Yahoo but ultimately revert back to Google, since Firefox allows for changing search engines with just a few clicks.

We don’t know all the details of what Mozilla and Yahoo plan to implement over the next five years; in December for example, Yahoo sites started telling Chrome and IE users to “upgrade” to Firefox. Google of course isn’t sitting on the sidelines — in January it showed Firefox users exactly how to dump Yahoo. The search engine wars are back.

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