More than 500 people gathered under a white tent at Cline Vineyards in Sonoma on Sunday for an afternoon of bidding at the 18th annual Sonoma Valley Harvest Wine Auction.The question of the day: How will the economy impact bidding? Last year the live auction raised $330,000, less than half of 2008’s take of $702,500. Organizers say 22 fewer lots played into the equation but the economic downturn was also to blame.