A Drinking Man's Guide to Beer:
While many beer experts will tend to specialty, and craft-beer types, the Beer Master at Beer Drinker's Hall of Fame focuses primarily on mass-prodcued beers, because, well, that's what most people drink here in the U.S.
Lagers, Ales, and Pilsners
Most mass-mass produced beers are one of three styles-- Pilsners, Lagers, and Ales. Over time, the government has blurred the lines between these types of beers, basing the titles primarily on alcohol content, when, in fact, the terms should have little to do with alcohol. In fact, the difference in terms should relate to the brewing process used, and therefore, the taste.
Beer Type #1: The Lager
A lager is brewed using bottom fermenting (the brewer's yeast sinks to the bottom of the tank) techniques, usually in a cooler. This type of beer is usually golden, especially in major-beer productions here in the United States, where beer drinkers like their beer golden instead of darker brown. Widely considered an "entry-level" beer-- it's common, usually clean and somewhat crisp. This is generally a lighter beer.
Beer Type #2: The Pilsner
Unfortunate for many fans of popular pilsners, a pilsner is a type of Lager. Both are bottom-fermented in cold settings, and there is truly little difference for the eyes (and tastebuds) of the average beer drinkers. Many German Pilsners are truly of higher quality than an average lager; however, in the U.S.A., the differences are quite subtle. You may find the pilsner to be more dry, or crisp than the lager, but the difference among mass-produced beers in the U.S. is extremely subtle.
Beer Type #3: The Ale
The true ales are beers brewed with warm-fermentation techniques, with top-fermenting yeasts. These beers are hard to qualify by taste alone, because there is an extensive range of true ales out there for consumption. The common thread, according to most experts, is a subtle fruit-overtone produced by a slightly faster fermentation process, due to the higher brewing temperature. This term has lost most of its meaning through the U.S. Government's dabbling in legal speak, relating an ale to an alchol contant, rather than brewing process. Your "Ale" is, in fact, probably a lager or pilsner, if purchased from one of the major North American Breweries.
