United States Patent and Trademark Office
United States Patent and Trademark Office or USPTO is the division of the US Department of Commerce that receives and issues trademark registrations for individuals and businesses. It also issues patents to inventors.
Trademarks, especially, apply to website sales. Many domain names contain generic keyword terms while some domains may include keywords trademarked by another party. In addition, websites may contain trademarks or copyrighted content. Depending on how the trademark is used on the website, it may be perfectly legal to license and use it from its owner.
For example, a PayPal logo on a website used by a registered merchant that uses PayPal for payments is fine. PayPal allows its merchants to use its logo on their websites to tell their customers that they use the secure and trusted PayPal service for payment processing.
However, using the word “PayPal” in the domain name is not legal unless it is used by a PayPal company. It could give visitors the impression that it is a PayPal-owned business when it is not.
As a website buyer, it is best to avoid purchasing websites that use trademarked words, logos, or marks without the permission of the trademark owners. You can perform a trademark search at USPTO’s website to verify its ownership.