I'm unable to rate anything in either iTunes, the Mac app store, or the iOS app store. If I rate an app 5 stars (or anything else), and then return to the search results, then go back to the app page the rating widget will appear as if I hadn't rated the app. The rating count does not increase either. It's has been happening for a while. I only just noticed the behavior a week or two ago when I got my iPad, but it may have been an issue before that on my Mac.
I'm assuming something may be wrong with my Apple ID, but I dont know what it could be.