I applied twice becauseI co-own a site with someone and wanted the accounting different. One was accepted, one was not. The one that was not listed Navigation and Domain Ownership.
I understand the first reason as I'm using Burst on that site and they show a lot of pop-ups, but the Domain Ownership one stumps me. The Whois info is the same for both, the only thing I changed was the email address in the signup. I suppose it could be because I applied twice? Dunno.
The rejected site is likely to make more on Burst than on Adsense showing Peace Corp banners, so I'm not going to bother with it. <added> Not that adsense isn't worthwhile because it is - just not for that site. </added>
I had a fascinating experience with the signup process (well, perhaps this highlights how boring my life is in comparison :D).
I submitted my site for AdSense consideration on Wednesday, and then last night around 1am I got a note saying that they needed more info on my domain ownership. Strangely, they didn't tell me why at first, nor give me info on providing proof... but they did so around 2am after I followed up on the original note.
At about 3:30am or so (I'm a nightowl!) I tried to send a fax to them, but got no answer.
Next chance I had, near 3pm, I tried sending the fax again and was successful. Within one hour, I got a note indicating my acceptance into the program.