Al Gore’s Current TV will become available in 7.5 million additional homes as part of a deal with Comcast, boosting the San Francisco-based network’s distribution to 28 million homes. The network, founded last year by Gore and legal services mogul Joel Hyatt of Atherton, is aimed at viewers 18 to 34 and features videos made by viewers who express their opinions. The network is also asking its viewers to create commercials for Sony that it can air.