So what exactly is the old world and why is it labelled as such? Old world wines are those have come from Europe - where they have been making vino for centuries as opposed to decades. Each country and has their own traditional wine laws, which dictate what grapes can grow where, the minimum level of alcohol by volume, even the residual sugar content.
The majority of the time wines are labeled by region rather than by the grape or grapes in the bottle. Why? In a word, terroir
You linguistic dorks out there, the word terroir means earth or land. In wine terminology terroir is often referred to as "taste of place." It is everything other than the grape and the winemaking that contributes to the flavor of the wine: soil type, slope, aspect (which direction those slopes face) and altitude. The thinking is that where the wine is produced is more influential on the finished product than the grape itself. If anything, the grape is the means by which the land expresses itself (rather poetic, no?). The grape in question was chosen because it proved to be the most effective medium for the job.
If one were to think of a bottle of wine as a work of art (A high falutin analogy but bear with me), the terroir is the painter, the winemaker the canvas and the grape is the paint. In new world terms (where variety and vintner style rules), the winemakers is the painter, the land is the canvas and the grape is once again the paint. There are exceptions to this rule, of course, but a sound concept to keep in mind when just starting out.
So click away and feel free to learn a little bit more about what could be your next favorite wine region!