With what tools? In theory, if you have a shared screen, and real-time voice communication, and remote whiteboards, and ideally real-time video, it should be basically the same as being there. The technology to do this is very, very expensive at the moment, though, which is presumably the raison d'etre of this startup.

You also miss out a lot on serendipity. Many of the best ideas that eventually become actual Google products happen because a bunch of folks are hanging out over beers, or they're sharing the latest cool thing they've stumbled across on the Internet, or they're shooting each other with nerf darts before going home. This sort of relaxed socialization seems to be exactly what you need to get creative ideas to bubble up to the surface. When you have to feel like you're "on a call" to get together with someone, you don't get this sort of spontaneous idea generation.