This year is expected to be the worst for auto sales in a decade. Automakers are slashing their ad budgets, but online they are spending more. After consistently leading the U.S. in advertising spending, the automotive sector has dropped into the No. 2 spot behind retail. Even as new vehicle sales decline, automotive marketers will spend nearly $3 billion online this year, up 21.6%. By 2012, automotive online ad spending will top $5.6 billion. Research shows that eight out of 10 consumers now consult the Internet at least once during the car-buying process.