The Yahoo advertising platform developed in partnership with nearly 500 newspapers may be able to reach 80 percent of online users in a geographic area, versus the 20 percent or less typically delivered by a single newspaper's Web site, an exec for the search engine told The Palm Beach Post. The network relies on behavioral targeting, sending users information on products they've recently browsed for online. For those concerned with privacy, Yahoo allows opt-outs. What do newspapers bring to the game? A local sales force.