Internet users will soon experience an increase in privacy and security warnings displayed by the web browsers that they use to connect to Internet sites.
Sorgente: Expect an increase in browser privacy and security warnings – gHacks Tech News
A high profile site that still uses Symantec certificates is PayPal
Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes, including fraud prevention, and subscription management. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
Sorgente: Stripe – Online payment processing for internet businesses | Italia
Mozilla uses it so I may consider them instead of Paypal!