Dayton

Media conglomerate Cox Enterprises Inc., betting its future on Internet advertising as newspaper and television audiences shrink, plans to spend $300 million to buy a startup that helps Web sites pool their ad space.

The all-cash deal with Adify Corp., to be announced Tuesday, represents the latest evolution for a media company that began more than a century ago with one newspaper in Dayton, Ohio. As new technologies emerged, Cox expanded to include radio, television and cable systems across the country.

Tim Harrington sits aboard the express bus from Mason, Ohio, to Cincinnati, his computer propped in his lap. He logs on, picks through his e-mail and begins his workday during the 30-to-40-minute rush-hour trip.

His commuter bus and buses in more than 20 other cities now offer wireless Internet, according to an informal survey by the American Public Transportation Association (APTA).