It's a site which has been airly described as "mostly cute kittens and elaborately concieved cupcakes", but Pinterest is undergoing a meteoric rise, and since Facebook bought Instagram, social media experits and marketing analysts have started to predict it will be Facebook's next buy.

Pinterest is a virtual pin board, where users can post up pictures of their favourite things. Other users can then re-post images that take their fancy. The site is mostly visited by women - only 20 per cent of users are male - and has become a digital catalogue of women's apparel and accessories, leading Amazon and Ebay to add Pinterest buttons to product pages.

In January, nearly 12 million users from the US and UK visited the site. It's now being touted as the third biggest social networking site. Socialmouths has unpacked this, gathering together three graphics.

According to a study by by ComScore conducted in November,  Pinterest ranks third in time users spend on the site, with only Facebook and Tumblr to contend with. The site is also behind Google+ for unique visitors -- with 4,855m.

Pinterest's unique visitors are rising rapidly, according to this graph from pinterest.com:

But the biggest news, according to Socialmouths, is that "Pinterest is referring more traffic than Google+, LinkedIn, and YouTube. Combined!"