You can’t appreciate it if you’ve never used an email client that does conversation tracking (a lot of people think that its a concept invented by gmail, but then again – all of them are MS Outlook users).

One of the most annoying problems with conversation tracking, is that if you deleted part of the conversation, the flow is lost forever (or at least until you go to the trash can, sift through 100s of messages already there to find the ones pertaining to your conversation and undelete them), and in a multi-branch conversation (the kinds that gmail can’t handle right now – compare to the BB approach to web forums vs. the tree approach), the structure can now be completely out of joint with who people intended for it to look. So in such a threaded view, you must never delete messages that may grow to be full fledged conversations, even if their content doesn’t seem interesting.

What is brilliant about the above GMail feature, is that you don’t need to go to the trash to recover lost messages, and you don’t need to fear the loss of zero-content, but structure carrying messages – because if you’d need them they can be easily retrieved (at least within 30 days).