Found this article ("Survey Says: Cell Phones Left Out") that discusses the increasing inaccuracy of polling and survey organizations, such as Gallup. I'm generally against polls and surveys, but I recognize that our society uses them in many ways (even if they're used to do all kinds of sneaky, tactical marketing and product placement).

Most polls take place over the telephone, but only over traditional land-lines. With more and more people opting for cell-phone-only life, the statistics and poll results are growing less and less representative of the actual population. Today, 3% of the U.S. population use a cell phone as their only phone, and over the next 5 years it may grow to 15%. Those numbers may sound small, but for a country of ~300 million people, 3% would amount to 9 million people, and 15% would be 45 million. That's gonna translate into a fairly huge discrepancy, and will usher in snapshots of society that are even more skewed and weird than they already are.