VVS is simply the abbreviation for "very very small" inclusions. Diamonds that are graded VVS contain imperfections that are considered minute and are extremely difficult (VVS1) or very difficult (VVS2) for a skilled grader to locate under 10x magnification.
In VVS1, they are extremely difficult to see, visible only from the pavilion, or small and shallow enough to be removed by a minor repolishing. In VVS2, they are still very difficult.
To check these out under the scope is quite awesome as the inclusions are usually nothing more than a speck or pinpoint. As you'll see, it's very important to examine diamonds clean as the smallest amount of dust could be mistaken for an imperfection. Most diamonds in jewelry stores that have been sitting in showcases have most assuredly collected some dust, if there are any VVS clarity diamonds in stock. If you go look at stones with jewelers, MAKE SURE HE CLEANS THE STONES YOU LOOK AT!
Generally in VVS1 clarities the incy bincy pinpoint(s) will only be seen from the pavilion (or bottom side) of the diamond. Here is an excellent example to show you of a VVS1 clarity and what to expect. This is a blowup of its plot on an AGS Report. Note the 2 red pinpoints in the 7:00 position. The first picture is a zoom in of those 2 pinpoints. Now note the tiny pinpoint just to the right of the 6:00 pavilion main. That is the 2nd zoom.
In the face up position it is impossible to see any inclusions.
In the VVS2 grade the inclusions are still considered minute but perhaps a few more pinpoints than are in VVS1 grade stones. Any VVS clarity, be it a VVS1 or VVS2, are immaculate under the microscope. Here are a few VVS2's to examine under the microscope.
In this zoom you can barely make out the 2 incy bincy inclusions making it a VVS2. There is a pinpoint in the 9:00 arrow and another between the 10 & 12:00 arrows.