According to the Thumbplay announcement, Calamera served as director of MobileMe service while at Apple. Despite the service's less-than-stellar reputation during his time there. Thumplay saw fit to scoop up Calamera. The newly branded CTO spent time at Danger Inc. and WebTV Networks, among others, before joining Apple.
As noted by PC World, the Snyder hire comes on the heels of her time managing security consultants at Microsoft and working on Windows XP and 2003 Server. What Snyder will do at Apple remains unclear, but the two variants of Safari (Windows and Mac) or the iPhone OS seem to be likely candidates for her expertise.
Source: Arstechnica.com