US web users conducted 9.6 billion searches at the core search engines during December 2007, representing a 3.9 per cent decline on November, according to market research firm comScore.

Search activity typically experiences a seasonal decline during December as many Americans spend time away from home during the holidays, the analyst said.

Market leader Google logged 5.6 billion core searches in the US during the month, followed by Yahoo at 2.2 billion.

As ever, Google remained the top search property with a share of core searches standing at 58.4 per cent.

Yahoo ranked second with 22.9 per cent, followed by Microsoft (9.8 per cent), Time Warner Network (4.6 per cent) and Ask Network (4.3 per cent).

Yahoo experienced the most significant market share increase, gaining 0.5 points versus the previous month.

Google also leads search activity on a global basis, recording 7.2 billion searches in December alone.

Yahoo ranked second with 2.4 billion searches, followed by Microsoft (963 million), and Time Warner Network (784 million).

EBay (up 3.9 per cent), Amazon (up 20.8 per cent) and Craigslist.org (up 6.3 per cent) were among the few to experience gains, as holiday shoppers contributed to increased search activity.