Is Podcasting turning into a viable media business? Maybe. Podshow this week add 30s shows to its network and plans a major marketing push to lure more podcasters into its fold, broadening the network of shows it can sell to advertisers. Meanwhile Paige Heniger and Gretchen Vogelzang, who’s “Mommycast” is about the joys of motherhood have signed a 12-month sponsorship agreement with Dixie paper products, worth more than $100,000.