This is just my opinion based on my observation over the past few weeks. It would appear to me that a lot of deal votes are based on who posted the deal and not the quality of the deal. An example would a 20% off coupon with more votes verses a 40% off coupon when the 40% off is obviously the better one.
Or sometimes when a deal gets near the top of the list for the day (or in the 23rd hour) the vote count really climbs fast.
Maybe I'm wrong about this, but again it is just my opinion.
Happy voting everyone!