TwoTweet is a new shopping cart service that integrates closely with your Twitter account, using it to log in and letting your customers "reply to buy." While it's a cute idea for very small-scale ecommerce, relying on the unstable and insecure platform that is Twitter may be the dumbest business decision you ever make.
TwoTweet isn't designed to replace shopping carts for larger sites, since you can only sell one item at a time with the system. But even for very small businesses, this is a dangerous venture. It doesn't matter if you're selling t-shirts and the occasional album: allowing access to an ecommerce environment with your social network as an identity provider is a supremely bad idea.
Say Goodbye to Guaranteed Uptime
I don't need to explain to ReadWriteWeb readers that Twitter has serious problems with stability and security. Building even a tiny and relatively inconsequential marketplace that depends on one of the most unreliable social networks is about the worst idea I've ever heard for using the social Web to do business.
Shades of Facebook Beacon
On the one hand, at least they asked permission to post to my account, which basically avoids the disaster that was Beacon, Facebook's attempt at broadcasting online purchases. But it still presents a problem in the value proposition: by and large, people don't want their purchases published on social networks, even if those purchases are not the kind that could have really serious consequences.
Another problem is that the site doesn't use OAuth, and I still had to fill out a lengthy form and create an account. With that in mind, I don't really see the advantage for buyers. It didn't save me any time over, say, using someone's simple WordPress site with the standard ecommerce plugins, and it's extremely limiting for sellers.