Presidential Polls: None the Wiser?

This just came to our in-box from TechPresident, seeming to confirm what many of us had suspected about the accuracy of polling this year as the pollsters try to figure out who's gonna show up:

Cell-Only Young Voters Lean Obama: You don't have to follow polls that closely to know of the fears that cell phones threaten to kick the leg out of modern surveying. A new Pew Research Center study finds that while among all voters, modeling off of land lines to capture the leanings of the mobile-only crowd is a satisfactory approximate. But, there's a "but" -- when it comes to those under 30, the gap between land and air widens considerably. Pew found that while 39% of sub-30 registered voters reached by land line are backing McCain, just 27% of cell-only voters lean his way. On the other side of the aisle, the trend goes the other way: just over half of land line voters under 30 are Obama fans, but that number jumps to 62% when the sample is limited to those who only use a mobile phone. If young people turn out in force on election day, those nuances might be multiplied enough to have serious impact on who becomes the next President. But our polls might be none the wiser.