Web browsers and search engines prefer secure web site URLs (using HTTPS) over standard web site URLs (using HTTP). Browsers now show warnings on a non-secure site that has a username and password prompt or a credit card field, hinting that your information could be stolen in transit. If it sounds scary, it’s meant to. Chances are low (but not impossible) that someone is going to be snooping your traffic on a wired Internet connection at home. But switch to WiFi and the risk increases. Browse at a coffee shop or on public WiFi and there’s a very real danger that someone sitting next to you could be logging into whatever site you’re logging into as you. It’s even worse if you use the same password on multiple sites — you’ve now potentially given someone the keys to your kingdom! Switching to a site to HTTPS prevents this information from being intercepted in transit.
In addition to added security and privacy, switching to HTTPS can come with an added performance boost if your hosting provider supports it. A new protocol, HTTP/2, which is only available via HTTPS, uses an optimized binary format, allows multiplexing, and allows servers to proactively push images and page assets to the browser. I won’t bore you with all the technical details here, but it’s much faster than using the standard version of HTTP/1.1.
Studies on the effects of switching to HTTPS on SEO are a mixed bag because SEO is such a complex beast, but most show a slight increase in ranking of an HTTPS site versus an HTTP site assuming all other things are equal. There are many, many factors that influence SEO ranking, so don’t expect that this one change will suddenly move your site from page 3 to page 1 … but given all the other benefits of using HTTPS, it certainly can’t hurt you if done properly.
Done properly, huh? What are the dangers? For one, you want to ensure you’re not creating “duplicate content”. If your site used to live at http://www.example.com/ and you enable HTTPS so that your site is now available on https://www.example.com/, there is a possibility that you could have both sites serving content from their respective URLs. This can create confusion for search engines as they will be seeing the same content and the same tags in two different places. Your “two” sites are potentially competing against each other for rank!
Whenever we transition a client from HTTP to HTTPS, we put the proper techniques in place to ensure their new site will be both user friendly and SEO friendly. We accomplish this through the use of 301 redirects and canonical tags. It may also be necessary to update your database and image tags to ensure content is being served from the correct URL.
It has been our standard procedure to setup any new sites we host with HTTPS enabled and forced on by default. We handle existing sites on a case-by-case basis, but almost all are eligible and would benefit from the upgrade.