The new triple style description need more clarity Rated 5 out of 5 stars

Update:
According to the description, (>>) should appear only when there are multiple people in the email message and (>>>) should only appear when a mailer group is involved. However, in my use, I see (>>>) not only for mailer but also for non-mailer messages with multiple people listed and see (>>) for the same as well.

Example: email message with say user1@domain.com, user2@domain.com gets tagges with (>>>), even though there is no mailer group in it. On the other hand email message with mailer group gets tagged with both (>>) and (>>>). Hence the confusion.

So, this is where it not clear how this is suppose to work. May be you can use an example to illustrate these two cases for clarity. Thanks

I don't understand what exactly needs to be fixed. What you describe is exactly the intended behavior. The idea of the add on is to make it easier for Thunderbird users to identify important mails. That's why it distinguishes 3 three types of mails, the personal level: Mails only sent to you (usually those are most important), mails sent to you but also to others and then mails that are sent to a list, but not directly to one of your mail addresses.

My understanding of a review is that you rate the add-on against its description, I was hoping the description makes the purpose of the add-on clear enough.

I like the idea with colored arrows, I'll add that as a feature request to the bugtracker.

Does not work with TB 24.0, but now it does ! Rated 5 out of 5 stars

It is a good add-on and was working fine while on TB 17.x Upgraded to 24.0 today and now every email show with (>) even for the ones that are sent directly to me and should be shown with (>>) instead. Anyone know how to fix this, would be greatly appreciated.

Update: Sept 19: After I wrote the review, the add-on developer updated to fix this issue for for TB 24.0. Great Job and Thank You for quickly fixing it.

This review is for a previous version of the add-on (0.5). 

Fix will be available shortly

I just uploaded version 0.6, which fixes the problem you describe. It will probably take a while until it will have been reviewed by the AMO team. Meanwhile, you may want to download a pre-release from https://dl.dropboxusercontent.com/u/1526797/tb-personal-level-indicator-0.6.xpi.