SAN FRANCISCO: Pinterest and Instagram, the image-based social apps, continue to move forward in step with both unveiling new options enabling users to purchase products via 'buy buttons'.

Pinterest subscribers using iPhones or iPads in the US will be able to buy more than two million products from later this month, with retailers including Macy's and Nordstrom signed up to sell on the platform. The facility will be extended to Android users and other countries later, the Financial Times reported.

Critically, users will be able to buy without leaving the app by clicking on a 'buyable pin' and using card details stored with Pinterest's payment partners; addresses are forwarded to the relevant retailer.

Instagram, which has so far preferred to focus on brand marketing rather than direct response, has also moved in this direction, announcing an expansion of its ad offerings to include action-oriented formats that will allow users to buy a product directly from an ad.

But where all the action on Pinterest takes place within the app, on Instagram users will click through to the retailer's site. Advertisers will, however, benefit from Facebook's targeting capabilities, reaching consumers based on demographics and interests, as well as information businesses have about their own customers.

"We want to leverage the best of Facebook's infrastructure for buying, managing and measuring the success of ads on Instagram," the company said in a blogpost.

These moves "completely change the character and nature of Instagram advertising", observed Debra Aho Williamson, principal analyst at research firm eMarketer.

The changes at Pinterest are also significant for one particular group: TechCrunch noted that the launch of Buyable Pins effectively cuts affiliate marketers out of the loop.

Bloggers had nurtured the site in its infancy, it said. And now, "Instead of bloggers earning money directly for inspiring a sale, Pinterest will earn money indirectly for transacting that purchase".

Data sourced from Financial Times, TechCrunch, Instagram; additional content by Warc staff