Facility to approve or reject new signed-up users. Get option to allow users sign-in only after email verification. It will not display your shop product price to the visitors until they log-in.
It sends an e-mail from particular user's outgoing SMTP mail server. Use your own smtp server for sending mail from Odoo.
Inspire your customers to buy again the already ordered products with "Buy it Again" feature. Get this Amazon like feature in Odoo E-commerce.