Clearwire (NASDAQ:CLWR) MVNO Karma officially launched service this week, offering a $79 mobile hotspot device and one gigabyte of free WiMAX bandwidth to get users started on its service. After that first data allowance is used up, Karma allows its customers to buy data as they go, charging $14 per GB. Customers must log in and create an account via Facebook (NASDAQ:FB). A blog entry from company co-founder Robert Gaal explains the company's target market as "people born on the Web." He said the company's Social Bandwidth approach encourages customers to share bandwidth with the public via the hotspot's Wi-Fi signal. Public users who connect via a Karma customer's hotspot must log in to get a connection, at which time they use their own bandwidth (either paid for or that first free gigabyte). The customer whose hotspot is used for the login gets rewarded with 100 MB of free usage. For more on Karma's offer, see this blog entry.