They just render the whole page inside a frame. If there was a resize on the page, the frame itself is resized as well, so you should see pretty much the same t

They just render the whole page inside a frame. If there was a resize on the page, the frame itself is resized as well, so you should see pretty much the same thing as the visitor. Note that this doesn't handle browser inconsistencies though. So something like that wouldn't be reflected in the "recording".