Unless you’ve been asleep under a rock for the last few years, chances are, Pinterest has touched your life somehow, either directly or indirectly. A new type of social media, Pinterest is a pinboard-style content sharing website that allows users to create and manage theme-based image collections over topics like special events, interests, hobbies, and more. Users can browse other users’ pinboards and “re-pin” other images to their own pinboards.

First launched in March of 2010 (at which time it was used by only a few friends and family members of founders co-founders Ben Silbermann, Evan Sharp (News - Alert) and Paul Sciarra), Pinterest has been growing rapidly, thanks to investments, and today is estimated to be worth in excess of $2.5 billion. Pinterest sees close to 50 million unique visitors from all over the globe each month, and today has about 100 employees.

The $2.5 billion valuation figure includes a new $200 million round of investment in the company led by Valiant Capital Management. Existing investors, including Andreessen Horowitz, Bessemer Venture Partners and FirstMark Capital also participated.

“Our focus is on helping millions of people discover things they love and get inspiration to go do those things in their life. This investment gives us more resources to help realize that vision,” said co-founder Ben Silbermann in a statement confirming the new funding.

The company is expected to use the funding, which is its first since a $100 million investment from Japanese e-commerce firm Rakuten last year, for product development and international expansion.

The Wall Street Journal reports that Pinterest has some unique advantages over other types of social media, and its content has a different lifecycle.

Brian Madden, executive director of social media for Hearst Corporation’s (News - Alert) Hearst Digital Media, told the WSJ that content that Hearst puts onto Pinterest can resurface months later when people continue to discover it. In contrast, posts on Facebook (News - Alert) and Twitter tweets produce “a lot of initial interaction” before fading.

“The longevity of content [on Pinterest] is very valuable to us,” said Madden. In December of 2012,  Hearst Corp. reported that it received more online traffic through Pinterest than Facebook and Twitter (News - Alert) combined.