Basically, it's just something that says that I think I know more about wine than most people. The certificate I have is the level 2 degree. There's also an Advanced Sommelier (level 3) and Master Sommelier (final level) that only I think 120 people in the world have.
http://www.mastersommeliers.org/
http://en.wikipedia.org/wiki/Sommelier
For my certificate, part of the exam had you blind tasting two wines, and you had to nail them both including:
Part of the World (Old or New)
Varietal
Age
Climate
Vintage
Aroma Assessment
Taste Assessment
So basically, it would go like this. Say you were given a red wine: "This is a new world red wine, from a warm climate. Viscocity is about medium, with little rim variation. The age of the wine is 3-5 years." (You need to get this before you even sniff the wine). So then you sniff the wine. Then you would go, "Lot's of dark fruit, like blackberries and cherries. Very little oakiness or tobacco, but it does have subtle hints of vanilla. Alcohol is about medium. Very little earthiness or minerality. Some floral aromas like lilac." Then you taste the wine. So now you go, "Sugars are medium minus. Tannins are about medium, with a medium finish. Alcohol is still about medium, and there is still very little oak which means it was probably aged in either French oak or stainless steel. Lots of fruit including the blackberry and cherry that was picked up in the aroma, and the finish has hints of the vanilla, and cedar." Then you give your final conclusion: "This red wine is from the New World, in a warm climate. The grape is a Pinot Noir from the Santa Ynez Valley in California, and is probably from a vinatage between 2003 and 2001." At this point they tell you that it is a 2000 Bordeaux from Chateau Margaux in the Medoc region of France, and that you failed.
I'm still debating on whether or not I want to keep advancing because it's very time consuming and the class times/locations are very, very limited.