Sorry, for not being clear. I'm not trying to checks if a domain already exists nor do I want to populate a table with millions or even hundreds of records.
It's the very same rational as the shelluser_blacklist file: There are user names that you want to block for obvious reasons. The same seems logic seems rational with domains/sites/email domains. Obviously anyone creating a site Microsoft, Dell, or HowToForge is bogus. Or say I were the Champions League and I was opening the ability for fans to create fan sites. I would want to block them from creating 20-100 sites with a domain_blocklist like:
Anyhow, by the two replys I received, it doesn't sound like this or anything similar exists.