most (not all, some contributions are QTVR-only due to historical reasons)
Javascript + HTML5 / WebGL
many, but depends on photographer's choice of file upload (newer event = more likely to work) and your device's capabilities. You may experience slow playback, distorted images or unexpected browser quitting if there is only limited memory/GPU power available.
Geographic Coordinates:
Latitude: 54° 16' 7.68" N
Longitude: 16° 4' 55.92" E Elevation: 0
Precision is: High. Pinpoints the exact spot.
Equipment: The panorama was taken with Peleng MC f 3.5/8 mm lens (set at f 8, ~ 1.5 m) on Canon EOS 20D camera, (set at: 1/180, 1/500, 1/60s (normal, underexposed, overexposed); ISO 200).
I used 8 bit source images. Each of the 5 source images were produced from 3 images (underexposed, normal and overexposed) by enfuse. This was to produce much better looking images, thanks to Erik Krause :)
Equi-rectangular image was converted to QT with registered version 1.6.2 of Pano2QTVR pro.