Claria Corporation, an online behavioral marketing firm, and its research division, Feedback Research, have announced the findings of a joint study on tax filing. The results show that 68 percent of web users opted to file their taxes online this year.

The IRS website saw the majority of online tax traffic, at 51.7 percent of total tax site visits. Intuit.com, which offers TurboTax, was the second most-frequented site, with 18 percent of all traffic. TurboTax.com saw 15 percent of those visits.

Online tax sites are gaining favor as broadband use increases and tax sites offer free tax returns. A recent comScore study found similar figures to those reported by Claria. It found that IRS.gov saw a 33 percent increase in visitors during the week leading up to tax day over the prior year. Over this period Intuit's TurboTax.com traffic rose 122 percent, and H&R Block site gained 28 percent more users.

According to the IRS, 64 percent of all tax returns submitted by April 8th were done so electronically.