I just stumbled through many optin page and found this, will it be ok if having adsense on opt-in page? With content and blog as sub directory? http://www.adsensearbitragevoodoo.com/landing1.html
You must be joking. You want people to OPT IN, not to click on your stupid ads or other links. But I guess those ad clicks are worth more to you than those addresses.
Yeah, you will get low CTR if you put the adsense at your opt-in page. People will click your ads, if they're need to find some information which are not in your site.