Aldi is a discount supermarket chain of German origin. Aldi is an artificial word composed of "Albrecht" and "discount". It was founded 1946 by the brothers Karl and Theo Paul Albrecht in Mülheim an der Ruhr wurde. It was only a small food shop then. In 1962, after it was parted into two companies, it became the supermarket chain we know today. It was the first real discount market at germany.
It is composed of two companies, Aldi Süd (Aldi South) and Aldi Nord (Aldi North), which cover different regions in the European and North American markets. Aldi was parted in those two companies 1961 and today they share nothing but the name. In germany every one of them has it's own territory. Both have international activities. Aldi nord is engaged at Belgium, the Netherlands, Luxembourg, France, Spain und Danmark, Aldi Süd at Great Britain, USA, Ireland, Australia and Austria (in Austria, it's called Hofer].
Aldi specializes in food, drink, sanitary articles and other cheap things one needs daily, cheap clothes and special offers like Computers that change weekly. It is the greatest wine seller in germany, for example. It sells mainly no-name products that are produced for Aldi exclusively, but are typically of high quality. Aldi maintains very low prices. The company can do this despite the relatively high quality level due to strict staff management and because it doesn't spend much money on shop decoration, commercials and such.
In germany, till about 1990 Aldi was thought to be a cheap shop wich sells bad stuff (although this was never really true). Most customers of Aldi were people who couldn't afford to buy somewhere else. Then, after the german reunification, mainstream families had to be more careful about spending their money and so Aldi became en vogue. The public realized soon that the Aldi products were not bad. This was boosted by a series cookbooks that only used products of Aldi for the recipes. This produced a kind of Aldi fandom.