The ads in question are those 15- and 30-second spots that automatically play before videos on YouTube, Yahoo, AOL and other sites - and they are either sold out in some markets or will be auctioned off at record prices, insiders tell POLITICO. <a href="http://politi.co/N0PZxj">http://politi.co/N0PZxj</a> NEW ADS HIT GOP SENATE CANDIDATES IN NORTH DAKOTA, MISSOURI. Majority PAC, a Democratic super PAC that focuses on Senate races, wil