After months of rumors and some tests spotted in the wild, Twitter is finally launching a button to make purchases on site.

Twitter announced Monday that it is testing a "Buy Now" button to let users shop from select merchants and artists directly from the social network. The button will roll out to a select group of users first before being introduced more broadly. The initial sellers range from brands like Burberry and The Home Depot to artists like Ryan Adams and Megadeth.

See also: Why Facebook and Twitter Are Embracing Ecommerce

The button represents Twitter's biggest step into ecommerce to date and is the result of many months of development and tests.

"In some capacity, we’ve been working on it since day one that I’ve been here," Nathan Hubbard, the former Ticketmaster CEO who joined Twitter a year ago as its first head of commerce, told Mashable in an interview. "I think you've seen us do a lot very quietly over the past year that informs where we are today."

Twitter had previously tiptoed into ecommerce with promotions that included letting users add products to their Amazon shopping carts by adding the hashtag #AmazonCart and partnering with Starbucks to let customers buy a $5 gift card for friends through the social network.

For the new shopping feature, Twitter is partnering with Stripe, an online payments service, to process transactions with "just a few taps." It's also working with several ecommerce services including The Fancy, Gumroad and Musictoday.

Twitter's "Buy Now" button Image: Twitter

Twitter's announcement comes less than two months after Facebook began testing a "Buy" button of its own. However, Facebook had the advantage of having previously accepted credit card payments from users for gifts and gaming purchases on the social network.

When asked how Twitter's commerce potential compares to social networks like Facebook and Pinterest, Hubbard emphasized two differentiators: the presence of "influencers" on the social network who can drive users to make purchases and the fact that Twitter is a truly real-time service.

"There is a real-time component to Twitter that isn't replicated anywhere else. I think that lends itself to items with a temporal component.. or anything with urgency," Hubbard says. Translation: Twitter sees itself as a powerful platform for more spontaneous purchases and limited-time offers.

"Part of the motivation just has to be to make the whole advertising process easier, to prove the returns and the conversion rates," Arvind Bhatia, an analyst with Sterne Agee, told Mashable in an earlier interview about the ecommerce efforts from Twitter and Facebook. "Sure, if it results in them being more of an acceptable platform for e-commerce... that's sort of gravy. But I don’t think the motivation here is to go all out and say, 'We’re going to be Amazon.'"

Hubbard acknowledged that improving ROI for marketers and boost revenue through transactions are both goals of the commerce strategy. That said, he stressed that Twitter isn't thinking about monetization in the "short run." If Twitter does a good job of connecting sellers and users, he says, "the monetization opportunities will be pretty clear."

"This is a bit of an extension of our brand or direct response advertising business," Hubbard says. "What we want to understand is are there specific products that will do better [on Twitter]... I’m not sure if someone is going to push the "buy button" for a vehicle, but someone may push order on a ride in real-time."