On Netflix’s developer site, there are some guidelines, including both “Dos” and “Don’ts” for delighting customers. One “Don’t” I found particularly interesting is
Non-user-initiated pop-ups are a Bad Idea.
Someone should tell that to their marketing department, or whoever is responsible for their awful pop-unders all over the web.
This reminds me of Anil Dash’s comment here: http://twitter.com/anildash/status/3162685112