I'd like to see a distributed way to do this, so you could share your ratkngs as though they were RSS feeds. The Learning Reghistry might do the trick. It's a mechanism for signing and sharing data 'behind the scenes' from server to server. "The Learning Registry is not a specific destination, portal or engine that educators will “go to”. Rather, it is an open technology framework to which any content creator can publish, and any technology vendor (e.g. learning management system, content aggregators, or application developers) can leverage for their applications." Scott Wilson is working "on a new project to share 'paradata' – things like reviews, ratings, comments and download/embed stats – between several new educational app stores being developed."