Row over interpretation over terms of service as Twitter shuts out system aiming to reward any user of Twitter based on other users'.
Twitter has blocked Flattr, a "payment" service in which people could get paid for having their tweets favourited by other users, from accessing its systems.
The move is the latest part of Twitter's strategy to build a wall around its revenues and prevent rival companies from leaching off any by diverting users - a policy that it has been following with growing intensity since its acquisition of Tweetdeck in May 2011.
Flattr describes itself as a "social microdonation service" which aims to "help creators get paid for their digital content". Users join Flattr, set up a monthly budget, and then click buttons - until now, including "favouriting" tweets on Twitter - to indicate their approval of content creators. At the end of each month, the budget is distributed among the recipients.