There are email clients, and then there is Postbox. Postbox certainly offers a turn towards Web 2.0, and it includes interface devices for social networking programs like Facebook and so on. Essentially, Postbox catalogs every piece of information in one's email, including text, addresses, links, photos, documents, and so on. When users click on an email, a preview pane pops which shows not only the email text, but all the other relevant information within the email. This version is compatible with computers running Windows XP and Vista as well as Mac OS X 10.4 and newer.