Americans conducted 14.3 billion core searches in October 2009, with Google sites accounting for 65.4% search market share, up from 64.9% in September. Microsoft sites grabbed 9.9% market share, up 0.5 percentage points versus September, according to a report from research firm comScore.

Yahoo! Sites accounted 18% of the US core search market in October, a decrease of 0.8% compared to 18.8% in September. AOL Network reported a decrease of 0.1% to 2.9% from 3% in September, while Ask Network share of searches remained flat.

In October 2009, Google Sites led the search market with 13.5 billion search queries, followed by Yahoo! Sites with 2.7 billion queries and Microsoft Sites with 1.5 billion searches. Bing experienced the largest growth of the top ten expanded search properties with an 8% increase in query volume to more than 1.2 billion searches.

According to the report, Ask.com search queries increased by 3% to 348m in October from 339m in September, 2009. AOL search network queries were 359m, a decrease of 2% compared to 366m.

Social networking site Facebook has reported a 14% drop in search queries to 331m in October, compared to 384m search queries in September. Searches on MySpace sites decreased by 4% to 472m, Amazon sites dropped 2% to 212m while eBay declined 1% to 617m.