punctuation.

unnecessary.

Thanks, Contrex.

I disagree. I would use the comma. However, I would remove it if the sentence read:


It was a race against time to stop the violence in the country where John lived.

Thanks, Mame.

Is there a reason why using 'this' instead of 'the' requires a comma?

The fact that John lives there is irrelevant. That comment is a parenthetical phrase, meaning that it's not necessary to the content of the sentence.

Parenthetical phrases: The parenthetical phrase has an important, often misunderstood, use. It is often used for thought interruptions. Information that is unnecessary to the meaning of the sentence is commonly set off and enclosed by commas. If the information is necessary, no commas should be used.

http://en.wikipedia.org/wiki/Comma_%28punctuation%29

Many thanks, Mame, for your reply and the website link.

Many thanks, Mame, for your reply and the website link.

By the way, is it called 'the website link'? If not, how do I describe it?