I cannot see a clear and easy path to uploading 360 panoramas shot with my Ricoh Theta to Photosynth without a Windows Phone or an iOS phone. If you have an Android phone, you are apparently out of luck?
The Photosynth desktop app and the online site (and Microsoft's desktop ICE) require you to upload 2 or 3 photos for the apps to stitch and then upload. The Ricoh Theta creates the panorama in just one shot. There is no functionality for the Theta through the desktop or online apps.
Apparently, only the mobile apps will upload a single Theta shot correctly, and the mobile app is only available for Windows Phone and iOS.
Ricoh's own Theta360.com site absolutely requires a Facebook login to use. I am opposed to Facebook and will never join it. So, apparently, the Theta was a pointless investment for me since nobody, including Ricoh, is willing to provide equal access to their technologies without locking it down to proprietary hardware or software platforms.