There is very little here about SSL certification, which is necessary for e-commerce.
I wasted a lot of time and money pursuing a level of SSL certification that was not necessary - stuff my web developers ought really have advised on.
In short, for me Organizational Verification was very difficult (I'd recently changed the business name, moved address, and changed telephone number, making OV a very wild goose chase, which was repeated all over once the 1 year certificate expired. Instead I needed only Domain Validation, which was cheap and easy.
I'm putting a few links here to help anyone looking in to this. http://security.stackexchange.com/questions/13453/are-all-ssl-certificates-equalhttps://stripe.com/help/ssl#is-there-anything-else-related-to-ssl-that-i-should-think-abouthttps://stripe.com/help/ssl