Here's what you get with a "Pro" account:
The "Pro" account allows you... create up to 75 projects and fill it with up to 500 images, 100 videos, 100 flash and 100 audio files. Also, you can custom design your portfolio by choosing from our wide range of quality backgrounds, logos and fonts. Finally, you will be able to link your portfolio to your own domain, allowing you to appear more impressive and professional!As of now, a Pro account is $40US for one year or $100 for a lifetime membership.
I hope this helps any of you who can't find this information elsewhere. Maybe it's on the site somewhere. I couldn't find it there or on Google.