If you are thinking of putting yourself or your company out there with your own domain name (e.g. cadnauseam.com), there are many, many sites out there that allow you to enter a domain name and see if it’s available. Don’t use them.
Why not? Because some of those sites will then immediately register that domain. You won’t be able to register it until that company decides to release it, which of course it will do if you choose to use that company’s overpriced domain registration services. This particularly unethical practice is known as domain tasting and is now the subject of a class action law suit.
It was the case that a domain registration company was legally entitled to hold a domain name for up to 5 days, before releasing it without any cost to itself: the 20c cost was refunded. Now that cost is set to become non-refundable, although there is some doubt as to exactly when this will take effect. When it does, that will put a big dent in this practice at the very least.
Even if domain tasting continues for the time being, there is no reason you have to become a victim of it. First, find a company that you trust that will register your domain for a reasonable cost, and which is prepared to give you complete ownership and control of the domain. There is no shortage of low-cost domain registration options out there, but check the fine print. I’m a very satisfied customer of Saratoga Hosting for both domain registration and web hosting services, and in the future I’ll go into more detail about exactly why that is.
Having found your trustworthy company, don’t bother with a special search. You could do a WhoIs search or just type your desired URL into your browser and see if it is already occupied, but you don’t even need to do that. Just go ahead and attempt to register the domain. If the name is available it will be yours.