A new article mentioned "comscore's rating" of ebay and craigslist (4 and 25 on the web, respectively).
Sounded like a list worth checking out.
So I went to comscore.com.
Only to be redirected and told I had the WRONG url ("loading page with correct domain name").
Why? Because I didn't use www.
Ok, I agree you should grab people who don't use www and show them the main site. However, it's poor customer service to scold them while you do!
Rude, rude, rude.
And honestly, the http://www.whatever.com/ vs http://whatever.com/ trade off should be invisible to the user. Most people won't know WHY they got that message, but it will cause them angst.
Remember: your average user doesn't love the computer and want to marry it the way your sysadmin, designer, and coders do. The average user is generally always worried they will do something wrong.
So don't tell users they did something wrong when they didn't!