I just came across this on digg: http://www.sourcelabs.com/blogs/ajb/2006/05/digg_this_button_on_your_own_s_1.html The script lets you have your own working digg button on your own page, very cool. Hopefully it might stop the continual 'please digg this' threads we have here
I have been trying to reverse engineer that script and it seems a bit dodgy for me. The javascript is a php generated iframe that loads the entire digg page into your site. So if digg is slow or they put a couple of lines of code to make their site break out of the frameset then the whole thing stops working. Hopefully they will release a proper way of doing it via an api or something.
You do with what you have The use of the iframe is explained by the fact that he wanted to have the animation when clicking the digg link and because to get the style, he needed the complete page info. In my opinion, this could have been done with a better method, but it's a proof of concept that it's possible. I guess Digg should start thinking about doing an API like you mentioned because this could help the thing grow even more, but the traffic to the actual page decrease just a bit (because we could digg directly on the the webpage), but it's a great idea.