The syntax for effective searching is both simple and complex at the same time. Let's start with a few examples and then move to an explanation.

If you wanted to find the phrase "protein shake" you would simply enter protein shake as your search criteria.

If however you wanted to find reviews containing the word "protein" and the word "shake", but not necessarily found together as a phrase, you'd enter protein AND shake as your criteria (the "AND" needs to be in upper case as shown.

If you wanted to find reviews containing the word "protein" or the word "shake", you'd enter protein OR shake as your criteria (again, with the "OR" in upper case as shown.

So, why do you have to put the AND and the OR in upper case when using them for logic? If you don't, they'll become part of your search phrase -- which you might want sometimes. For example, you might want to search for the phrase "carbs and calories", in which case you'd enter carbs and calories which would be taken as phrase.

Having given examples, here's the explanation (for people that don't learn best from examples).

Words without "boolean qualifiers" (e.g. AND OR) between them are treated as a single phrase, not as separate search words. So, if you search for dannon lite you'll find reviews that have the words "dannon lite", together, in that order, but would not find a review that had the phrase "dannon is lite". If you wanted to find reviews that had the word "dannon" and the word "lite", but not necessarily together, then you'd use dannon AND lite as your search criteria (the AND must be in all caps). If you wanted to search for posts that have the word "dannon" or the word "lite", then you'd search for dannon OR lite.

You can also have phrases and words in the same search, so for example, dannon lite AND yogurt would find reviews that have the phrase "dannon lite", and the word "yogurt" anywhere in them.

Finally, if you don't capitalize AND or OR, they will be treated as search words. Done incorrectly this could be bad because just about every review will have the word "and" or the word "or" in it. You might however want to use them if you were searching for say "peanut butter and jelly" as a phrase.

OK, that was the same explanation two different ways. Hopefully that helps everyone! :-)