In advance of the Oct. 25 worldwide release of Taylor Swift’s Speak Now album, three tracks will be previewed and made available for purchase on iTunes. A track will become available each week during the three weeks leading up to the album’s release. Additionally, a 30-second preview of each track, along with a brief interview with Swift, will be featured each week on Comcast on Demand, online at XfinityTv.com and on E! News Daily. The title track will be previewed on Oct. 4 and made available for purchase on Oct. 5. “Back to December” will be previewed on Oct. 11 and placed online for purchase on Oct. 12. “Mean” will be previewed Oct. 18 and made available for purchase on Oct. 19.