Credit cards will never touch the SkinXchange servers. All credit card processing is handled through Stripe.com and you can read more about their security here.
At no point will SkinXchange ask for your Steam login credentials. All data that we require from Steam will be gathered by connecting your Steam account through Steam Connect, which allows us to retrieve that information to send trade requests to your account.
Any personal information gathered such as name, email, phone will never be redistributed to anyone else. We keep ALL of your information private.
We may use your contact information for notification purposes only. Such as sales you've made, current promotions, etc. We will not spam you with unrelated content.