Isn't the threaded conversations feature in Gmail the best? Rather than having a gazillion emails with the same person, you can have them all in one handy spot. Yeah, it's great. Well yesterday, Gmail announced a new unread option within conversations.
Before, if you marked an email (which was a part of a conversation) unread, the entire thread would be marked unread . . . and if you have 15-to-20-message-long emails like me, that's a whole lot of searching before you find the right one. Well now you can mark unread to an opened email, and it will only keep that one unread, making it easy to retrieve later.
For now this feature only works on your computer (and not your cell phone).