Two of the hottest features on IRS.gov, www.irs.gov, are the "Where's My Refund?" service and Free File, the public-private partnership that offers free e-filing and tax preparation for eligible taxpayers. Taxpayers used the "Where’s My Refund?" service more than 4.5 million times in February to search for the status of their refund and more than a million tax returns have been filed using Free File.

By the end of February, taxpayers had downloaded 195 million files, which is 82 percent of the 236.6 million files downloaded all of last tax season from January to April 15. In addition to downloading, many of the most popular IRS forms can be filled out on-screen then printed.

The IRS Web site sits at No. 2 on the Lycos 50 list and sits at No. 8 on the Yahoo! Buzz Index. Both the Lycos 50 and Yahoo! Buzz Index lists are based on the number of people who search each site for specific words or subjects.