You mean to run ads on and make money or do you mean that you want to send traffic to it?
Adsense used to work with blogspot AFAIK and a lot of those were $thing.blogspot.TLD
It could also be related to the content topic
I've also noticed that in the last while Adsense has got a lot stricter about enabling sites that it considers to have "problems", though how it decides that a site has issues is a bit lacking in detail