Sometimes this control item appears and you can orbit a point cloud (using Ctrl+click-n-drag). This is particularly nice to get a spatial feel for a site (e.g. Mayan ruins of Palenque, http://photosynth.net/view.aspx?cid=0c71b1c4-8113-4bc4-bf4d-71ec4d9c6749).
You can also turn off the photos by pressing the 'p' key. The synther automatically detects objects, and the viewer places halos there. When the synther sees that you've taken a number of photos all pointing at the same thing, it calls it an object. If you take a number of photos from the same place, it calls it a panorama.
Check out Fere's rubik's cube. This is an excellent example of an object. For a panorama, see crater lake. Here are the links:
Photosynth looks for 3 or more images whose cameras' "look direction" are all pointing at the same point. It puts a halo around every such point. (There are a few other minimal requirements in the form of synthiness and complexity of the point cloud)
Just got back to check this post. Tnx, madeeds n Marvin.
P.S. There's notification for comments on synthn, but not on forum posts. I guess they're workin on that, as the forum is rather new.
I would hope so. It's rather hard trying to find responses to my posts.