Spears, who has topped the list for three of the last four years, lost out to "American Idol" in 2004.
Although the 24-year-old pop star released an album of remixes, "B in the Mix, The Remixes," in November, it was the, Sean Preston Federline, on Sept. 14 that brought her the most attention, Yahoo said Thursday.
Following Spears were, in order, 50 Cent, the Cartoon Network, Mariah Carey, Green Day, Jessica Simpson, Paris Hilton, Eminem, Ciara and Lindsay Lohan.
The list of overall top searches, all of which were entertainment related, "shows us that people are fixated on the activities of pop culture icons," Yahoo "Buzz Index guru" Erik Gunther said in a statement.
Yahoo Inc. has claimed that its search index spans more than 20 billion Web documents and images, though that figure is virtually impossible to verify because there is no official auditing system.
Of the top news searches, "tsunami" led all other stories, followed by "Iraq" and "Michael Jackson trial."