The OXtender for Thunderbird is an addon for Thunderbird (and Lightning) to provide users full access to appointments and contacts stored in the Open-Xchange Server and use Thunderbird as a rich client online and offline.
For Human Eyes Only is a Firefox plugin that lets you post in a way that prevents computers from analyzing your messages. The plugin converts your messages into images in a way that makes it hard for computers to extract your message, while genuine humans can still read it.
Lightning is a calendar application which works with the popular Mozilla Thunderbird and SeaMonkey mail clients. It lets you manage multiple calendars, create your daily todo list, invite friends to events, and subscribe to public calendars.