[This is part of a series I'm putting together for a talk at the OTBC about classic web blunders.]
Whose business are you promoting?
You've decided it's time to start that new company. You've got a name all picked out, let's call it Widget Co. Unfortunately, widget.com is taken. So are widgetco.com and widget-co.com. But, widgetco.biz is available.
So you buy the name, invest in business cards, letterhead and advertising. You get out and start networking, leaving voicemails, and talking to anyone who will listen about your company.
You don't know why that VP of Biz Dev you met at that chamber meeting never sent you that email he said he would send. You know the email with his product requirements so you could give him a proposal for his next big purchase.
Unfortunately, the guys who own widgetco.com are in pretty much the same work you are, and they start getting random hits on their website, and random phone calls for work they can do. And they get the email to email@example.com from that VP of Biz Dev, and THEY bid the work.
Make it easy
You're better off changing the name of your company than having a similar domain name to a competitor.
You don't want to use tricky misspellings that could become someone else's domain or overly long domain names. Real words are best, but go ahead and invent a word if you need to. It worked out pretty well for Verizon and Comcast.
KMF @Employeeze: Re: You figured .biz, .info, .us would work fine
There is merit to what you say, but there is also the fact that sometimes a "clever" spelling is going to be more descriptive. I spent many dollars and time with my own biz consultant on this one ;)