It would be folly, of course, to run more than two or three (at the most) adjectives together. Furthermore, when adjectives belong to the same class, they become what we call coordinated adjectives, and you will want to put a comma between them: the inexpensive, comfortable shoes. The rule for inserting the comma works this way: if you could have inserted a conjunction — and or but — between the two adjectives, use a comma. We could say these are "inexpensive but comfortable shoes," so we would use a comma between them (when the "but" isn't there). When you have three coordinated adjectives, separate them all with commas, but don't insert a comma between the last adjective and the noun (in spite of the temptation to do so because you often pause there): a popular, respected, and good looking student
That passage is a little misleading. Nothing wrong in more than 3 adjectives if they are of different classes. The classes of adjectives mentioned here are basically these seven - observational (beautiful, delicious), size (small,gigantic), shape (round, square), age (old), color (red), origin (Italian, Dravidian), material (wooden, silk), qualifier (Nilgiri, hunting, basketball). In fact we are supposed to string the adjectives in that order of classes. We do it naturally though. "We played using a faded, small, round, old, red, american, basketball, hoop" is how we would describe a hoop with 7 adjectives! (in this case, even the commas can be dropped, like we usually would)
As said above, an "and" is used when 3 or more adjectives of the same class is strung together. PKB almost did it right, though he had two classes of adjectives. "Arab" and "Muslim" were in one class (qualifier) and "African" was in another class (origin). Thus no AND should be used there. Note that in the example in the above quote, all three adjectives were of the same class (obsrvational) and that is why the AND was needed. Now, PKB can make a case that the three adjectives were almost in the same class, and that is why I said he was precariously close to being correct!
It is because AND is not supposed to be used for adjectives other than in the special (and very rare) case of using 3 or more adjectives of the same class, that the line takes a different meaning if the adjectives also happen to be nouns. That is because nouns are supposed to be strung with ANDs or ORs and not commas like adjectives are.
Just wasting time, of course. These posts will surely be moved to the "Know your english" thread.