In some instances worse things happen. You could receive an email in your inbox, for example, making same claim: your domain is about to expire. Click on a link and you've given (unknowingly) permission for your domain to be transferred. A few days later you might discover your web site not working, your email turned off and your domain information completely unavailable.

This is called "domain name slamming", and it is named after practice that some highly unethical long distance phone companies employ. These companies will, at least provocation, change your phone company to themselves. You could cash a check, return a post card or use any number of other means to "give permission" to change. Some of most unethical companies have been known to just change your service without even asking.

The moral of story? Keep good records of where your domain names are registered. If you do get an email or a letter, go directly to your domain registrar's web site and renew domain yourself. Don't click anything in email, respond or send back a letter. Just go to web site and renew. This way you can be sure you understand exactly what is happening, and this way you can be positive that nothing else is occurring.

And oh yes, stay away from those registrars who engage in this practice. At least, that's my humble advice. I find whole tactic unethical in extreme, and personally, I will go to extremes to not do business with any registrar who slams.

http://www.uspto.gov/web/offices ac/notices/guide299.htm

As stated by United States Patent and Trademark Office, http://www.uspto.gov/ "A mark composed of a domain name is registerable as a trademark or service mark only if it functions as a source identifier. The mark as depicted on specimens must be presented in a manner that will be perceived by potential purchasers as indicating source and not as merely an informational indication of domain name address used to access a web site." In other words, use of a domain name must not be used simply as an address to direct customers to your web site, but must be used to identify products or services of business claiming trademark, which provides products or services via Internet.

If you're in market for a domain name, you may want to consider searching Trademark Electronic Search System, http:/ ess.uspto.gov/bin/gate.exe?f=login&p_lang=english&p_d=trmk prior to registering a domain name. By researching trademark regulations and knowing your rights, whether you hold a trademark or a domain name, you may be able to avoid possibility of litigation.