Publishers seem to hate Readability. First was Ben Brooks dedicating a week to blocking posts from being parsed by the service. Now AppAdvice is jumping to conclusions, accusing the site of stealing content through shared links. They claimed Readability directs these links to the parsed article and not the original content. I think they're wrong. If you click that link while not signed into a Readability account, it takes you directly to the page and not the article that’s hosted on Readability’s servers. It does provide a “bar” at the top to use Readability if you’d like though, similar to StumbleUpon. If you’re anti-iFrame then this will probably rub you the wrong way.
That being said, I still think Readability collecting money on behalf of publishers that have not signed up for the service lands them in an ethical grey area.
Update: I guess I was way off on the above comments. Looks like they were redirecting to their own site. Full coverage at The Verge.