What is daypop?

Okay, some of you guys from the world outside the U.S., what is this daypop thing and why are you coming to the blog from that site? I'd really like to know, because I can't imagine that this blog, which is so local in emphasis, would at all be of interest to anyone at the Guardian, or in Bulgaria, or Sweden, or Germany or Portugal. Please, please, let me in on the joke!