Image-based social networking service Pinterest has relaxed its sign-up policy, opening the site to all. Previously, people needed invites to become members and “pin” online images onto its virtual “boards”. Launched in 2010, Pinterest became the fastest-growing site ever, passing 10 million users in nine months. Although it has tried different money-raising techniques, the company has not yet disclosed a commercial plan. “They’re one of the main sites that serve the so-called social collectors, people who like to curate information across the web,” said Forrester Research analyst Darika Ahrens. Read the full story at BBC News.