Incentivised blogging

It has become commonplace for mobile apps to offer some kind of feature enhancement in response to a user's review of the app on its relevant app store. Would such a system be possible with off-app-store reviews, typically blogs?

Obviously with human intervention it would be possible for the publisher/developer to check the review, an then unlock features on the user's account. An automated system might be possible where the users submits a url to the blog post, which is then downloaded by a bot and scanned for keywords and sentiment analysis.

Due to the cost overhead of developing the keyword and sentiment analysis, an incentivised blogging solution would probably only make sense as an independent service shared by many app developers/publishers.