I don't think you understand what foliohd does. They're not squatting on hundreds of domains in advance. This is how it works, based on 1 minute glance of their site:

- you create portfolio, but it's by default served as a subdomain

- then you decide that you really want to use "mchichol.com". You register through them instead of buying it yourself.

That's it. It's customer's domain, not theirs. They also specify that domain is yours if you ever want to move your site elsewhere.