Placing comma in right place is important and sometime confusing. Placing comma in wrong place can change the meaning of the sentence. Mr. Ben Yogoda, a Professor of English, has written a very useful article in New York Times on use of comma. He writes in one of his article;

“You can glimpse a reason for this codification — which emphasized consistency rather than sound — by looking at the opening of the Second Amendment of the Constitution (1789):

A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.

There are three commas. The one after “state” would be used today; the one after “arms” would not; the one after “militia” is ambiguous; and all three have caused a world of hurt, confusion and argumentation over the last 223 years. As Adam Freedman wrote in this newspaper in 2007, a Federal District Court ruling invalidating the District of Columbia’s gun ban (subsequently upheld by the Supreme Court) held that “the second comma divides the amendment into two clauses: one ‘prefatory’ and the other ‘operative.’ On this reading, the bit about a well-regulated militia is just preliminary throat clearing; the framers don’t really get down to business until they start talking about ‘the right of the people … shall not be infringed.’” More generally, the funky comma protocol muddies the crucial link between the importance of militias and the right of people to bear arms.”

To read the complete article on correct use of comma, please click on the link below. It will be a time worth spending.

http://opinionator.blogs.nytimes.com/2012/05/21/the-most-comma-mistakes/

Fayyaz