It does not work with @{any letter}. Try @b or @x - they will search for content by user 'b' (http://github.com/b http://github.com/b) and user 'x' (http://gith

It does not work with @{any letter}. Try @b or @x - they will search for content by user 'b' (http://github.com/b http://github.com/b) and user 'x' (http://github.com/x http://github.com/x).