AOL's chief executive Steve Case is now a paper billionaire after shares in the number one online service provider continued to climb this week. With more than 8.5 million shares to his name, his holdings are estimated to be worth $1.18 billion based on AOL's closing price of $138 -- not bad for a man who started life developing topping for Pizza Hut. AOL -- with 14 million members -- is one of the world's top Net companies, which is perhaps part of the reason why its share price has increased six-fold this year alone. And although analysts are still projecting bigger and better things for Net companies in the New Year -- and AOL in particular -- more and more are beginning to voice concerns about the sector overheating. ®