Zimbra is a next-generation enterprise messaging and collaboration system. It features an Ajax Web client with conversation views, fast email search, Web service mash-ups, shared calendars, document authoring, and IM. The server also syncs to MS Outlook (via MAPI), the Apple desktop (via iSync, iCal, and CalDAV), POP/IMAP clients, and mobile devices (BlackBerry, smart phones, HTML Web browsers). A version of the Web client, Zimbra Desktop, also works offline with any POP/IMAP server. Administrators can control live backup/restores of individual or groups of mailboxes, hierarchical storage (HSM) and clustering, LDAP directory configuration, Web services integration with existing enterprise applications, and integrated anti-spam and anti-virus.
OpenInviter is a script to import contacts (address book data) from email providers like Yandex, Lycos, Rambler.ru, Live / Hotmail, OperaMail, GMX.net, Mail.ru, Mail.com, GMail, Yahoo!, Rediff, AOL, and KataMail. It can import from content management systems like SimpleMachines Forum (SMF), Drupal, Social Engine, Wordpress, PunBB, Joomla, JamRoom, and PhpBB. It also imports from social portals like Twitter, Facebook, Hi5, Friendster, Orkut, Myspace, and LinkedIn. It offers basic "tell a friend" features.