Japan-headquartered e-commerce giant Rakuten has taken its first step to collaborate with Pinterest, the social network that it recently invested $100 million in, after announcing that three of its Japanese services — virtual mall Rakuten Ichiba, Rakuten Travel and Rakuten Recipe service — now include ‘Pin It’ buttons to allow images and content to be shared to pinboards on Pinterest.

The move is the first time that the two sites have paired their services together since the closing of Pinterest’s funding, which valued the social bookmark and curation site more than $1 billion, and it follows Rakuten’s commitment to help broaden Pinterest’s audience and explore new opportunities, particularly in Japan.

To that point, two of the integrated sites are targeted entirely at Japan-based Web users. Rakuten Travel is a dual English-Japanese language booking site for hotels in Japan while Rakuten Recipe is an entirely Japan-focused site. Ichiba is global but has significant visibility in Japan, where it is the country’s largest shopping site.

As part of the introduction, Rakuten has also introduced a ‘how to’ guide to Pinterest.

pinterest rakuten 520x262 Rakuten begins Pinterest collaboration, adds Pin It buttons to three key Web services in Japan

In the announcement, Rakuten reveals that it has “plans to accelerate the rollout of Pinterest’s services in Japan”, but it is unclear whether that could include more than just expanded support for sharing to Pinterest.

Pinterest is continually talked about for its potential to boost e-commerce service, and we’d  be interested to see if some form of integrated payment or heightened tie-in with Rakuten may be forthcoming.

Coincidentally, this week we spoke to Rakuten’s executive officer of global marketing Mark Kirschner who didn’t reveal details of upcoming plans between the two, but did stress that the tie-up signals the next phase of e-commerce, with reference and curation becoming an important part of ‘discovery shopping’.

Kirschner explained that the coming together was based on a “meeting of minds” between the two companies but he also stressed that it is an open relationship which leaves Pinterest free to pursue opportunities with other e-commerce players.

Speaking after the close of its latest round, Pinterest said the additional capital will enable it to ‘improve its service’ and expand globally. The company stresses that the Rakuten investment is the start of a strategic partnership that will help it expand not only in Japan but also the 17 other markets Rakuten operates in.

Pinterest is the third most visited social network in the US, as of March, and the site saw an estimated 11.7 million visitors in January this year. Its popularity has surged over the last year, with statistics showing that its traffic grew by more than 6,000 percent over the final six months of 2011.

Hat tip @Mona, image via Flickr / Free-stock