comScore, Inc., a leader in measuring the digital world, released its monthly comScore qSearch analysis of the U.S. search marketplace. Google Sites led the explicit core search market in September with 66.1 percent of searches conducted, an increase of 0.7 share points from August 2010.

The September 2010 qSearch figures reflect the impact of Google Instant Search, Google’s new feature that delivers results in real-time while users type their query.

U.S. Explicit Core Search

Google Sites led the U.S. explicit core search market in September with 66.1 percent market share, followed by Yahoo! Sites with 16.7 percent and Microsoft sites with 11.2 percent. Ask Network captured 3.7 percent of explicit core searches, followed by AOL LLC Network with 2.3 percent.

More than 16.0 billion explicit core searches were conducted in September. Google Sites ranked first with 10.6 billion searches, followed by Yahoo! Sites in second with 2.7 billion and Microsoft Sites in third with 1.8 billion. Ask Network accounted for 593 million explicit core searches followed by AOL LLC Network with 362 million.

U.S. Total Core Search

Google Sites accounted for 62.9 percent of total core search queries conducted, followed by Yahoo! Sites with 19.2 percent and Microsoft Sites with 12.5 percent. Ask Network captured 3.4 percent of total search queries, followed by AOL LLC with 2.0 percent. Google’s share increased by 2.4 percentage points, primarily due to the impact of Instant Search.

Americans conducted 17.7 billion total core search queries in September with Google Sites leading with 11.1 billion searches, followed by Yahoo! Sites with 3.4 billion and Microsoft Sites with 2.2 billion.

“Powered By” Reporting

As a part of comScore commitment to accurately represent the continued evolution of the search landscape, beginning this month, comScore is providing insight into the share of algorithmic Explicit searches that are powered by Google and Bing, and branded as such to the consumer. Google’s “powered by” share is composed of searches conducted at Google entities, as well as AOL and most of Ask’s MyWebSearch. Bing’s “powered by” share is composed of searches conducted at Bing entities as well as Yahoo! Web Search, Yahoo! Image Search and Yahoo! Video Search. Some of Yahoo!’s in-channel searches, such as movies and finance, are still provided by Yahoo!

In September, 69.1 percent of searches carried organic search results from Google, while 23.5 percent of searches were powered by Bing organic results.