Clickbank and Paydotcom are both excellent ways to start processing payments online.

Each of them have their own distinct advantages.

Clickbank processes all of the payments for you. They are like a central clearing house. They pay your affiliates, deal with the tax issues, and cut you a check. A drawback for some folks would be the limit on how high of a % you can give your affiliates. Also, their refund policies are very pro-consumer.

With Paydotcom, you are using a paypal account. That will give you much more flexibility as to how you want to pay out your affiliates. It also gives you full control over your own refund policies. But, to quote good ol' uncle ben, with great power comes great responsibility. As mentioned earlier, you will have to be careful to make sure you have a paypal business account, or you might see yourself in a bit of a fight with them. The tax implications are also slightly different, as you will have to make sure you have the appropriate forms for all of your affiliates when you pay out.

Just out of curiosity, what are your goals? Are you trying to sell a physical product, a digital product, or a membership?