Pinterest, a social pinboard site, has thrown open its doors to anyone who wants to join.
"We're thrilled to announce open registration," Pinterest said in a blog post Wednesday. "For those of you who haven't joined Pinterest yet, this means you can sign up without waiting for an invite ... In addition to using your Facebook or Twitter login, we're also opening registration so you can sign up with just your email address."
The social network previously took new users by invitation only.
Zeus Kerravala, an analyst with ZK Research, said he's only surprised that it took Pinterest, which launched in beta in March 2010, this long to open up its registration.
"All of these social sites are valued on the size of their active user base," Kerravala said. "Keeping it limited by invite-only limits the value of it for Pintrest and all of its users."
However, Kerravala noted that the Pinterest team hopefully was using that time to prepare the site for what could be an onslaught of new users.
"Clearly, the volume of usage is going to go up significantly," he said. "Giving a few people a good experience is much better than giving lots of people a poor experience."
Pinterest is like a shareable scrapbook. Users can create various pages of interest by pulling in images from around the Web. If someone spots an image - of, say, a beautiful garden, a hairstyle, shoes or a thoughtful quote - she can use a plugin to grab it and add it to her board.
People who follow the user can see her pinboards, repin their favorite images and comment on them.
The site is a collection of collections, which offers a look into the worlds of fashion, travel, cooking and religion, as much as it offers a view of the people who are sharing their passions.
Online traffic monitor comScore called Pinterest the "fastest growing social media site" in terms of unique visitors and clicks on search engines.
According to Experian Hitwise, Pinterest became the third-most-visited social network this past spring, trailing social heavyweights Facebook and Twitter but ahead of Google+.
Experian also noted that women account for 60% of the site's purported 20 million monthly visitors.
