content: It's for SSL certification. Any site can self-certifty SSL. It doesn't mean that the traffic is securely encrypted. The purpose of a certifying agency is to ensure that sites claiming to use HTTPS are actually using strong encryption. It's one of many centralized weaknesses of the current internet. Self certified HTTPS has already been stigmatized, but honestly it just comes down to people preferring to be told that something is safe rather than figuring out whether something is trustworthy on their own.