Note that the usual method for doing so (a CNAME on the bare domain) prevents you from adding other resource records (such as MX) on the domain.
1. http://joshstrange.com/why-its-a-bad-idea-to-put-a-cname-rec...
That's interesting. Currently I have 2 different domains at 2 different registrars. In each case I have the bare name, www and other subdomains as "A" records, not CNAME.
So it doesn't matter if people use the www prefix or not, since both point to the same IP. And with this configuration I've had no trouble with MX records.
If the goal is www/no-www transparency, there are other ways to do it, but using a simple DNS setup seems like the least hassle.
The main reason to redirect to one or the other is to have a canonical URL scheme for search engines.
Great point. And candidly I never actually do this myself (CNAME on the bare domain), I just point it at the server and let apache/nginx handle the redirect.
Edit: I'm wrong. See tadfisher's comment below.