This clearly does not work though... Quoting Google's Adam Langley:
"Unfortunately, many CAs decided to ignore it, presumably on the assumption that Microsoft would be forced to back down. We've done this dance with MD5 and 1024-bit certificates and we know how it goes. Here's a quick list of CAs that issued more than 2000 certificates extending into 2017 with SHA-1:
GlobalSign nv-sa: 75,312 GoDaddy: 41,606 GeoTrust: 40,429 Comodo: 37,789 Verisign: 34,927 Terena: 9,444 Thawte: 8,735 Internet2: 8,637 Network Solutions: 8,077 Entrust: 5,542 AlphaSSL: 3,458
We would all have liked CAs to have acted either when the Baseline was updated (2011) or when Microsoft laid down dates (Nov 2013) or when Chrome talked about doing this at the CA/B Forum meeting earlier this year. It is unfortunate that that 2016/2017 dates are being ignored.
If you run a site and want to be insulated from this sort you might want to consider getting one year certificates. CAs like to sell multiple years of course but doing renewal once every three (or more) years means that you have a significant risk of loosing the institutional knowledge of how to do it. (E.g. the renewal remainder email goes to someone who left last year and you then have a panic when it expires). Additionally, very long lived certificates are not insulated from from these sorts of changes and you may need to replace them during their lifetime anyway."