Once upon a time (i.e. the mid-90s), using a common word for your URL guaranteed tons of easy traffic. A lot of people didn't know how to use the internet, and when they wanted jokes, they would literally type "jokes.com" into their browser window.
This happened thousands of times a day, every day. It doesn't happen anymore.
The result is a lot of expensive URLs that nobody wants. When someone does buy one, it's because they don't know how the internet works, which means the website they put there is usually insane. A few favorites:
Cats.com
Friends.com
Clothing.com
Internet.com
Politics.com
News.com
Computer.com
Fun.com
Music.com
Happy.com
Sad.com
So what's at your favorite URL?