Very useful and used extensively by experts, Mail Filters aren’t often set up by novices, but Thunderbird makes them really easy to use.

Why would you want to use Mail Filters?

There are many reasons you might want to filter messages – have a folder for emails from family, or important emails, or unimportant emails – any time you want to keep some messages separate from your Inbox, or make some stand out in your list of emails.

I’m going to work through an example to show how this works.  Recently I signed up to Freecycle which I heard about a while ago but never investigated.

First impressions: it’s a great idea but isn’t making the best use of technology, and I dislike systems that try to make you sign up (and give your details) to additional services you shouldn’t need – in this case a Yahoo! ID.

I digress, if you don’t have a Yahoo! ID, you can still join in but you can’t utilise all the features, you can only be part of the mailing list – at least I think I’m right about that!  A mailing list is a system whereby an individual sends an email to “the list” and everyone subscribed to the list receives a copy of the email in their Inbox.  Well, after a couple of days my Inbox was overflowing with Freecycle mailing list messages.

Time for a filter

  1. First, create a new subfolder in your Inbox, by right-clicking on Inbox and selecting New Folder… from the menu that pops up:
  2. I created a folder called Freecycle:
  3. Next, go to Tools > Message Filters… and click on the button labelled New…
  4. A window titled Filter Rules will open.  At the top there will be a text entry box labelled Filter name.  Enter a name for your filter here, I called mine “Freecycle Emails”.
  5. Now for the interesting bit.  In the same window, there is a section headed For incoming messages that: where you can set up “rules” to match against emails that arrive in your inbox.
    Keeping it simple, the default rules is to find any email where the “Subject” “contains” text that you enter in the next box.  You could filter on who the email was from, or when it was sent – there are other options too.
    The Subject line of all of the emails I receive from freecycle start with [GroupAreaFreecycle], where GroupArea is the area of the Freecycle group (note the use of the square brackets).
    I may join more groups in future, so I want to find any emails with the text “Freecycle]” in the subject line.
  6. In the next section of the window, at the bottom, I need to tell Thunderbird what to do with the email.  So far I’ve only really talked about moving emails, and that is what I’m going to do in this example.  You could use the filter to mark, copy, forward, delete the email etc.
    The default action is to Move Message to so I leave that.
    In the box to the right I can browse for the folder I created earlier.  So, when I’ve finished my Filter Rules window looks like this (Click to enlarge):
  7. I click on OK and close the Message Filters window.  Now, whenever an email from a Freecycle mailing list arrives, Thunderbird will automatically move it to my Freecycle folder for me, keeping my Inbox uncluttered.
  8. You can also run filters manually, by going to Tools > Run Filters on Folder.  Here’s the result after running the new filter on my Inbox:

You’ll notice on the image of the Filter Rules window that there are plus and minus buttons next to the rules and actions that can be taken.  This is because you can specify very broad or narrow rules to match emails against.  The minus button will delete a row, the plus button adds a row where you can specify a new rule or action.