Experian Hitwise has just released its analysis of the top 300 search terms for 2009; Facebook was the top-searched term overall for the first time ever. Four variations of the term “facebook” ended up in the top 25 of the list, for a total of .67 percent of all searches.   MySpace, Craigslist, YouTube and Yahoo were numbers two through five.

Google was the top-visited Web site for the second straight year, with 6.7 percent of all 2009 U.S. visits through November. While Yahoo Mail garnered 4.4 percent, Yahoo itself represented another 3.36 percent.   The top 50 Web sites accounted for 39 percent of all U.S. visits throughout the year.

The significant changes in the top ten most-visited Web sites were that Facebook replaced MySpace in the number three spot, with MySpace dropping to number five; YouTube jumped from tenth to seventh spot, while Ebay dropped from sixth to tenth.

Here’s more data from Hitwise.