Domain names are so cheap everyone should have at least one. Registrars like godaddy and aplus can register a .com domain name for you for between $7 and $10 per year. I own several. You'll pay around the same amount for “privacy” where the registrar will act as a level of indirection between your contact details and every random crackpot in the world with a TCP connection. The best news is there are still lots of great domain names available. I just checked now and the following are still up for grabs:
If you think ahead you can register a domain and use the power of sub-domains and amplify the usefulness of your domain. For example although I considered registering excelisnotadatabase.com notadatabase.com is also up for grabs. I could create a sub-domain like excelis.notadatabase.com for excel-specific rants, and then later open up xmlfilesare.notadatabase.com.