• Eight killer Thunderbird extensions
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• mailredirect extension
  The mailredirect extension for Mozilla Thunderbird adds ability to redirect one or more mails to one or more recipients.
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• Remove Duplicate Messages
  If you have duplicate messages (e.g. from merging folders or downloading messages several times) you can use this tool to find and remove them from the selected folder and its subfolder by rightclicking on a folder and choosing "Remove...
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• Thunderbird: auto delete duplicate messages
  The add-on searches a given folder for duplicate messages and automatically deletes them by tagging all duplicates with a delete flag and one message with the keep flag.
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• View and update Google Calendar with Thunderbird
  a detailed tutorial on how to sync and update Google Calendar with T-bird using the previously-mentioned Lightning calendar extension.
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• 10 must-have Thunderbird Addons (+ 25 more) » MakeUseOf.com
  
  Mozilla Thunderbird is an Outlook-like email client, but way better. It's free, it's multi-platform, it's multi-lingual and most importantly, it's highly
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