We reported earlier that payments startup Ribbon had launched their “in-stream” payments system for Twitter, allowing users to make purchases without leaving the Twitter environment by making use of the Twitter Cards feature launched recently. About an hour after the feature launched, Twitter shut it down, invalidating the feature. A workaround is currently in place, directing users to a ribbon.co checkout page instead, but this diminished functionality does not align with Ribbon’s goals. The startup is currently attempting to resolve this matter with Twitter.