Its pretty much handy, infact, i had observed few days back while reading my mail its similar to Google Experimental Search - Shortcuts
When I say shortcuts, its just for moving the mail cursor for up and down along with the opening part of it which comes very handy have a look at the shortcut table below,
Key Action
J Selects the next result.
K Selects the previous result.
O Opens the selected result.
<Enter> Opens the selected result.
/ Puts the cursor in the search box.
<Esc> Removes the cursor from the search box.

Did I said about “Google Experimental Search” above? have a look at clicking on itself. 3 new ideas, not so new
a. Alternate views for search results b. Keyword suggestions. c. Keyboard shortcuts
December 14th, 2009 at 5:37 pm
Nice article thanks for sharing!