Google Now Factoring HTTPS Into Ranking; CloudFlare On Track to Make it Free

Relevant announcement from Google: http://googleonlinesecurity.blogspot.in/2014/08/https-as-ran...

Relevant HN discussion: https://news.ycombinator.com/item?id=8146433

Probably the most effective way to get site owners to switch over. I've told clients in the past that SSL could potentially be a positive SEO factor for cheap - it's at that point they begin to change their minds.