Twitter is trialling a new system to let users purchase items simply by clicking on a 'buy' button in a tweet.
A small percentage of US users will be given the option to buy goods using just a few taps.
At first, only a small number of Twitter's test partners will be able to feature the button in their tweets.
It signals a new direction for the social network, which has so far relied on advertising for the majority of its income.
In a statement, Twitter said: "This is an early step in our building functionality into Twitter to make shopping from mobile devices convenient and easy, hopefully even fun.
"Users will get access to offers and merchandise they can't get anywhere else and can act on them right in the Twitter apps for Android and iOS; sellers will gain a new way to turn the direct relationship they build with their followers into sales."
Among the individuals and companies to partner with Twitter for the trial period are rapper Eminem, fashion house Burberry and Aids-awareness brand Red.
Twitter says an entire purchase can be completed in a few taps.
After tapping the buy button, users get product details before being asked to enter their shipping and payment information. Once entered and submitted, the order information is sent to the seller for delivery. Twitter insists the payment information is encrypted and safely stored. It is unclear whether Twitter gets any commission from sales.
In April, BSkyB - the owner of Sky News - teamed up with Twitter to let users watch or record Sky programmes by clicking within a tweet.