To me, polls are worthless. The raw polling data is subjected to all sorts of manipulation by the polling agency, and these manipulation ("weighting") can throw numbers in all sorts of directions. Even the raw data, depending on the collection technique, is subject to gamesmanship.

A great article from the University of Pennsylvania's Center for Organizational Dynamics describes a study the center did on the 2004 election. Titled, The Unexplained Exit Poll Discrepancy, it gets into how polling does and does not work. http://www.appliedresearch.us/sf/Documents/ExitPoll.pdf

In short, when it comes to elections, the old cliche "figures lie, and liars figure" pretty much summarizes this marketing technique.