Social network site Pinterest has received a US$100m investment in a round led by Japan’s biggest e-commerce site Rakuten. According to the Wall Street Journal, the funding values Pinterest at US$1.5bn.

The round includes follow-on investment from existing investors Andreessen Horowitz, Bessemer Venture Partners, and FirstMark Capital, as well as a number of angel investors.

Now the 16th most visited site in the US, Pinterest functions like an online mood board, allowing users to ‘pin’ photos and images, and follow others’ collections.

In a statement Rakuten said the funding will allow Pinterest to continue improving its service and expanding its community globally.

“While some may see e-commerce as a straightforward vending machine-like experience, we believe it is a living process where both retailers and consumers can communicate, discover, and curate to make the experience more entertaining,” Hiroshi Mikitani, CEO of Rakuten explained.

“We see tremendous synergies between Pinterest’s vision and Rakuten’s model for e-commerce. Rakuten looks forward to introducing Pinterest to the Japanese market as well as other markets around the world.”

The investment also marks the start of a strategic partnership between Rakuten and Pinterest to help expand in Japan and into Rakuten’s 17 other global markets.

Ben Silbermann, co-founder and CEO of Pinterest, said: “Our goal is to help people discover things they love, by connecting people through their shared interests. Bringing Rakuten on board gives us an amazing opportunity to move a step closer to this goal.”

Most of the site’s users are female – with 97pc of the site’s Facebook Likes being made by women.