I meant that you can usually figure out the meaning of parentheses by looking at the pattern of use within the notation. Most of the time, it doesn't matter whether you're getting the chords from a book, a website, a napkin or a Ouija board channelling your great-aunt Vidalia. Nor does it matter much what type of song it is. You shouldn't even have to consult a book's tablature legend, unless you're a newbie. Chord notation is surprisingly consistent, and though there are a number of variations, differing systems seldom conflict enough to produce ambiguous readings.

It's just that some symbols denote different things, depending on placement and neighboring symbols. But if you need even more information to divine the meaning, chances are whoever created the notation did so without regard to existing conventions--they should be flogged and banished from the village--, because several hundred years of usage have sufficed to resolve all the common notation problems.

Note that I'm talking specifically about chord notation, not tablature or the notation of rhythm or special playing effects (bends, slides, damping...) There is still a disappointing lack of consistency in these areas.