Paypal X - adaptive payments - what is this?

I'm a little confused, all these different types of product and it sounds like it will do all the same thing? Can someone please explain to me in plain english what are the differences between these products? what can you do and cant you do with each product? Example of where it's used.

Adaptive Payments enable developers to build apps that process transactions. App builders can control the entire tra开发者_运维问答nsaction within a single interface.

Express Checkout helps you to increase conversion rates and attract new customers. It streamlines the checkout process for buyers and keeps them on the merchant site after making a purchase.

Payflow Pro is a flexible payment gateway solution that can be used with any internet merchant account to process credit card transactions online.

Website Payments Pro is a low-cost, all-in-one payment solution that is both a merchant account and payment gateway. You can accept credit cards and PayPal payments directly on a website.

Please don't take this as an authoritative source of information, but here's what I know from trying to find a payment method for my own apps:

Adaptive Payments is an API that lets you do things like charge someone, and pass on the money to someone else, while taking a commission. Or charge someone and pass on 40% to party A and 50% to party B and keep the rest as your share, stuff like that. Normal payments, but with the added advantage of being able do things with the money once it comes in.

Express Checkout is the standard buy with paypal button that you stick on your site. takes the user to paypal, and puts money in your paypal account.

Payflow Pro is a payment gateway. The user will never see anything of paypal. You send the gateway the credit card number you want to charge, how much you want to charge it for, etc, and they deposit the money directly into your merchant account in your bank, after taking a commission.

Website Payments Pro is like payflow pro, but here they'll handle the credit card capturing business - just pass the user along to paypal and the money comes into your merchant account.