I purchased Dior Diorshow Maximizer Lash Plumping Serum a couple months ago, and put it through the ringer, so to speak. According to Dior, the Maximizer contains hydrolyzed soy proteins and lots of other scientificky-sounding stuff. After eight weeks of use, testers found the Maximizer increased lash volume by 52%, lash length by 38%, and lash curl by 73%.
So, does it deliver? Well, I did notice some difference in my lashes, though I don't know how to quantify that difference. My lashes do appear a bit longer (though it is hard to tell in the pictures because my lash tips are blonde), and more voluminous. I wouldn't say the Maximizer caused my lashes to grow, rather it conditioned my lashes, allowing them to grow longer (without breaking) and have a longer life before falling out. I also noticed those fine little baby lashes grew thicker and longer.
Application is like that of a mascara. It has a spiky, silicone (I think) brush with a little nub at the end. The Maximizer is formulated for use under mascara, which gives you instant results, as well as on it's own as a nighttime treatment. You can use the little nub to apply the serum to your eyelid right at the lash line to get the serum right down into the base of the lashes so it will work while you sleep. I'm puzzled by the use of the word "serum" because the stuff is a white cream. When I think serum, I think of a light, almost gel-like formula, not a thick cream.
One Coat Primer:

One Coat Primer + One Coat Mascara (at the start of the 8-week test):

Personally, while the Maximizer did produce instant results when I wore it under mascara, it was a bit too much for me for daily wear. Furthermore, I found my mascara flaked off when I wore the serum underneath. After that, I limited my wear to nighttime and special occasions only.
Being that I am a visual person, I like to see results, not just read about them, so I have a lot of pictures.
More pictures after the jump - and I mean a lot more pictures!