Review for ThreadVis by jinzougen
Rated 4 out of 5 stars
Great add-on. Only one problem which makes me give it a 4-star rating:
It seems like the threading algorithm doesn't take messages from other folders into account. For example, in my inbox I have a lot of replies to emails I've sent out, and the visualization puts a grey square where my outgoing emails should be. The outgoing emails are in my "sent" folder but I guess ThreadVis doesn't see/consider that.
To create your own collections, you must have a Mozilla Add-ons account.