Fun fact: this was added by an engineer who just really wanted to be able to click through a whole conversation – or click from one flagged message to the next. Or, from one Unread message to the next. Or, from one message written by someone to the next message they wrote. All without leaving the keyboard. Here’s how it works:

Either click Ctrl + Shift + the up arrow on your keyboard, or click More Actions on the Yahoo! Mail toolbar, Extended Navigation and then Configure…

The “Configure Extended Navigation” window opens, where you can choose if you want to use this shortcut to go from one message in a thread to the next, or skip from one to another of the connected messages described above –Flagged, Unread, or from a certain someone. Done? Click OK.

Now just use the keys Ctrl + Shift and the up or down arrows to go to the previous or next message in the sequence. Groovy! And if you don’t like them keys, you can always also go to the toolbar with your mouse/pointer and click More Actions, Extended Navigation, and either Previous in Thread, Next in Thread, or Oldest Unread. Hip hip!