Email, RSS and newsgroup client with integrated spam filter
Thunderbird is a full-featured email, RSS and newsgroup client that makes emailing safer, faster and easier than ever before. It supports different mail accounts (POP, IMAP, Gmail), has a simple mail account setup wizard, one-click address book, tabbed interface, an integrated learning spam filter, advanced search and indexing capabilities, and offers easy organization of mails with tagging and virtual folders. It also features unrivaled extensibility.
Mozilla Thunderbird is a free and open-source cross-platform email, news, RSS, and chat client developed by the Thunderbird Project.