FTA: 3rd party ads, issues with preserving SEO rankings and a staged approach (only certain parts of the site on HTTPS). The more technical article is better:

FTA: 3rd party ads, issues with preserving SEO rankings and a staged approach (only certain parts of the site on HTTPS). The more technical article is better: https://www.wired.com/2016/09/wired-completely-encrypted/ https://www.wired.com/2016/09/wired-completely-encrypted/ I've made the move before and have definitely experienced the SEO drop, even with all 301 redirects and sitemaps reconfigured.