Pearltrees, the visual and collaborative library that lets you easily organize and bookmark information in tree-like structures, finally launched its Android app for phones and tablets today. The service started out on the web in 2009 and then came to the iPad in 2011 and the iPhone last year. Android, however, as the company's CEO Patrice Lamothe told me last week, was always one of the most requested platforms and the team also expects this launch to help it quickly grow its user base.More...