Ever felt that the red flag in Mail.app doesn’t offer you enough flexibility?
Flagit! is a plug-in that offers Mail.app users customisable flags of as many different colours as you like, as well as question and exclamation marks.
It is packaged as a plug-in for SIMBL 
, an Input Manager that allows application-specific hacks for Cocoa apps (like Mail.app).
It is not heavy on documentation. Pay close attention to the installer screen, because it offers you all the information you will get on how to use its new features:
Once installed, you can access its features through the “Mark” option in the contextual menu. Highlight the email you want to flag, Control-click (or right-click) on the email and choose the flag you want:
The Customize option opens a preference pane with room to edit the default flags and create as many new ones as you need:
It also provides the option to colourise the text of the email that you have flagged. Combined with the option to colourise the backgrounds of emails (which I do through Mail Act-on — Leopard users this way ), it can produce a riot of colour in your inbox.
If I wasn’t very happy about marking emails done or needing attention or waiting for a response with the keywords feature of MailTags , I could imagine using this, and benefitting from the additional visual help of coloured flags.
Flagit! works with Tiger and Leopard and is shareware (USD 8). You can download a 15-day free demo from the developer’s web site .
UPDATE: Users report in the comments that Flagit! doesn’t play nicely with the WideMail plugin. The comments also contain some tips on uninstalling Flagit!
Merlin Mann 
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