HellBound Hackers are a team of Profession Hackers that can -*test*-('") the security of your website for you - for a fee.
What interests us Riddlers is a set of challenges to tackle that they provide. Many are hacking based challanges, like viewing sources to find weaknesses etc.
There are other challanges similar to NotPr0n and some of the phases here, htat involve finding the answers hidden in images or sound files.
There's a wealth of information to help you out and to inform you.
As you gain experience in HBH you can see your ranking:

I'm too n00b to be very high.