A typical hour of HD recording is somewhere between 4 and 9 GB, I currently have a 3.5 hour movie which is sitting at 31GB.

My local CBS affiliate's web site has done this, with what I would presume to be success. They link to a competitor station or local newspaper's site for a story they don't have coverage of, and on the way out, you get a little extra ad for their trouble. The external links are placed in similar fashion to their internal links... looks the same until you click it. Of course, the competitor's site opens in a new window, so you'll come back to theirs to continue browsing.