MailTags 4.1.6 | MacOSX | 9 MB
MailTags goes well beyond keywords to allow a range of tag data including Keywords, GMail Labels, Finder Tags, Projects, Tickle Dates, Importance, Notes, Events and Tasks. Use MailTags flexible tagging window to set and edit tags on messages. New to MailTags 4 are full GMail Label support.
MailTags displays your tags in both message lists and full message view making it easy to view your tags at a glance. Draw attention to important messages by prioritizing a message's color based on project, importance, tickle dates or more.
MailTags integrates into Mail's search and smart mailboxes so that your tags become powerful way of finding messages. MailTags also organizes your time sensitive messages into tickle mailboxes so you can always see messages that need attention today, tomorrow or soon.
Mail's rule system is made more powerful with the addition of MailTags actions to automatically add tags to new messages, and even inherit tags from older messages in a discussion. Combine MailTags with Mail Act-On to create sophisticated tag based workflows work on demand and when sending messages.
Home Page - http://www.indev.ca/MailTags.html