This is, quite simply, the best tech article I've ever read. (Yes, the Frog has stopped referring to herself in third person, at least for today.)
It may not be the best gauge of what's good for a business. (Commenters have noted, beneath the article, that this piece is 100% anecdotal; is there any evidence of a company that's successful because it sends users off-site?) But it is an accurate reflection of user experience. At the end of a visit, people feel better if they can leave with something. An article they can email to others, some html copy-and-paste text to put on their blogs, a download, a music clip, a tangible product...
In other words: something useful that moves with them, off the site and into the flow of their daily lives.
Could there be anything more viral than that?