Mozilla is planning on restricting the functionality of unencrypted http sites (more here direct from Mozilla), only giving full functionality to https sites. This will be another nail in the coffin of Firefox IMHO, all it means is even the less trustworthy websites will have https in future. It really adds very little to security that your link is encrypted, given the low chance of interception, though perhaps the browsers apply more stringent security policy to https sites.
That led me to the website Lets Encrypt. Later 2015 this site will provide free certificates to enable https on websites. It's supported by Mozilla, Akamai, Cisco, The EFF, so should be successful. You can get certificates for $10 or less already, and may be able to get free certificates (though they didn't work for me), but this will increase adoption. One key factor is shared hosting, who may charge a fee for each website hosted, or make it difficult / impossible to install the certificates. All in all though Lets Encrypt seems like a positive move.