I have a blogsite with 2000+ feed reader by feedcat, but only 50+ feed reader by feed burner! so is it possible that google ads into feedcats??? How many feed reader require to post adsense into feed burner???
Yes, there is no limit regarding feed burner readers count. But after apply for adsense for feeds, you have to wait some weeks, and regarding email subscription readers, I am really surprised that google ads display in emails sent by google feedburner to subscribed readers, and now I am earning some extra money from these ads.
Google owns FeedBurner, so Adsense can easily be integrated in those feeds. Feedcat does not have that relationship, so it's not possible to tie together your Feedcat account and your Adsense account.