Even after Radiohead offered its latest album online for whatever price fans wished to pay last fall, there remained enough buyers to send last week's hard copy release of In Rainbows to the top of the sales charts.

The physical copy of Radiohead's seventh album has reached No. 1 on Canadian, U.S. and U.K. music charts, according to figures released by Nielsen SoundScan and other groups this week.

However, the 122,000 copies of In Rainbows sold in North America paled in comparison to the 300,000 copies of the band's last studio effort, the 2003 album Hail to the Thief, during its first week of release. The completion of that album ended the band's contract with music giant EMI.

The lower number is believed to be a result of the band's decision to make In Rainbows available first as a digital download with optional pricing on its website.

The 10-track album's music files, however, were of lesser quality than that of a CD and the download option was removed from the website before the release of the album's physical version on Jan. 1.

While the band has not revealed specifics about the online initiative, including how many times the album was downloaded or how much money fans chose to pay, the decision made headlines worldwide. Early interest and heavy traffic crashed the site on the first day.

Music industry trade sources later estimated the number of downloads in the tens of thousands, while consumer research firm comScore later said that, according to a study it conducted, more than 60 per cent of the downloaders chose to pay nothing for the digital files.

While Radiohead was far from the first recording act to try this online release format, the experiment is believed to have been a catalyst for other prominent artists, ranging from Nine Inch Nails to Madonna, to move towards alternative distribution methods that cut out the traditional record label.

On Wednesday, the Grammy Award-winning British rockers also announced they will hit the road for a two-part North American tour that will sandwich a previously announced slate of U.K. and European dates this summer.

Though no dates or venues have yet been set, Canadian stops will be Vancouver, Toronto and Montreal.

With files from the Associated Press