most (not all, some contributions are QTVR-only due to historical reasons)
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.
I have chosen this VR panorama to be my personal favourite of the year 2005 because it showcases the crazy soccer fever here in Germany that leads to extraordinary campaigns and events.
This is the virtual soccer equipe SIEGENIA-AUBI Titans from Siegen, Germany, in the Cologne Rheinenergie Stadion. This will be one of the soccer World Cup games stadiums in 2006. I took the panorama after the Titans were announced by the stadium speaker and had a small warming up on the 11th of November 2005, the day Carnival starts here for some months in Cologne.
Beyound the Titans, SIEGENIA-AUBI is sponsoring the "Windows Of The World" panorama photography competition, too (link below). Perhaps they should hold some money back for buying some modern soccer shoes ;)