Pinterest has quickly become one of the top 100 sites on the web, but while the company has kept quiet about its data, marketers are wondering if the usage and engagement numbers are as impressive as its traffic.

Analytics software company RJMetrics wondered the same thing so it collected data and analyzed nearly one million pins from a random group of Pinterest users. The company found that Pinterest is retaining and engaging its members as much as two to three times more efficiently than Twitter did at the same time in history.

“The site is structured so that members become creators themselves by ‘liking’ the pins of other people they follow,” RJMetrics found and CEO Robert Moore told VentureBeat. “The end result is a powerful network effect that eclipses the retreating activities of Twitter users.”

In fact, 80 percent of pins are re-pins, compared to Twitter’s history where only 1.4 percent of tweets were retweets.

RJMetrics also took a look at the content behind pins and instead of pointing to a single source, pins feature a variety of content from more than 100,000 different sources. The most popular domain was Etsy.com, which powered just over three percent of pins.

Google was close behind — though Moore was careful to note that most links point to Google Image Search, which is misattributed content from third-party domains. Rounding out the top five are Flickr with 2.5 percent, Tumblr with 1.1 percent, and weheartit.com at 1.0 percent.

While it’s still early in the game for Pinterest, it’s growth can’t be ignored. Not only are people signing up, but they’re sticking around and continuing to interact with content and other members. It will be interesting to see how Pinterest continues to grow in terms of product, but for now, it’s a great place to start building a community.

[Via: VentureBeat, Image credit: Anja Redenbaugh]