Twitter has pulled the rug out from under Flattr, a service that let users send a digital thank you to anyone favoriting one of their tweets.
In a blog post today, Flattr noted that it will no longer be able to offer its service because Twitter felt it was a violation of the social networking giant's API terms.
"Recently Twitter contacted us and told us that we are violating their API terms citing [a] clause saying 'Your advertisements cannot resemble or reasonably be confused by users as a tweet. For example, ads cannot have tweet actions like follow, retweet, favorite, and reply. And you cannot sell or receive compensation for Tweet actions or the placement of tweet actions on your service."
Twitter did not immediately respond to a request for comment.
Flattr's post noted that the clause makes sense because it would stop companies from selling retweets and followers and because "it's an understandable rule to keep the Twitter network clean."
But Flattr also argued that Twitter's decision is "strangely stomping out innovation on their platform."
Flattr's complaint is hardly the first. Over the last year or so, Twitter has angered a number of developers by clamping down on access to its API. Twitter's position has been that it wants to maintain a consistent user experience across all first- and third-party services, but it's also clear that Twitter wants control over revenues that can be generated by the microblogging platform, regardless of whose client someone is using.