When should one use a 'www' subdomain?

Question

When browsing through the internet for the last few years, I\'m seeing more and more pages getting rid of the \'www\' subdomain.

Are there any good reasons to use or

Answer 1

Just after asking this question I came over the no-www page which says:

...Succinctly, use of the www subdomain is redundant and time consuming to communicate. The internet, media, and society are all better off without it.