It seems like the difference between high-security sites that have hidden files and the ones that don't are pretty much restricted to the type of enemies you fight. If you're fighting a Zaibatsu Defender in the first or second layer of security, you've got something promising. If you're fighting a Password Lock or an Autodefense, probably not. Given that the website names seem to be randomly generated (barring keywords that describe site type), is it important to build a list of names at the top of the page describing what you can get from a website type?
Materials Supplier / Discussion
This is the discussion related to the wiki page Materials Supplier.