Google Reader is the newest addition to Google Labs. Fantastic AJAX interface, very like GMail, in which you can see the design ideas that could remain consistent all through Google interfaces.
However the most important aspect of this the ability to add any metadata tag/labels to each post as you like. This is very much in the Folksonomy vain. This is only a very small feature of Reader but quite a sea change for Google to include it....of course I cannot see any way in which these tags are used???? Database of Intentions then :)