I had been requested this much less sometime ago, and did not have a very good answer...

It is possible to valid reason why a website which has an SSL certificate wouldn't use https:// for his or her entire site instead of http://

Exist Search engine optimization issues? Performance overhead for that server?

Just just in case it matters, we use Light stacks.

Thanks!

  1. for every request your computer data is going to be encoded and and decoded this can increase unnecessary strain on server and would may also increase response duration of ur site.

A couple of reasons:

  • Producing SSL content takes additional work so performance of the busy site happens to be an problem
  • Most (all?) browsers stop delivering referrer info with demands to monitoring customers using your site may well be more challenging
  • You might need to be more deliberate in the way you serve pages to obtain browsers to cache them correctly
  • When the page is SSL, all content loaded around the page ought to be SSL, too, to prevent mixed-content alerts within the browser serving dependencies like scripts, images, etc. under SSL isn't necessarily convenient

Note, however, that many sites do do that. For instance, some of the banks I personally use are always https, for the various components that do not want it.

Using SSL/TLS does no more add greatly overhead: http://world wide web.imperialviolet.org/2010/06/25/overclocking-ssl.html

(As @erickson stated inside a comment in this article, probably the most computationally costly part may be the handshake. Good comment generally.)

I believe you might get a loss of revenue in performance in some instances because browsers will not keep content acquired via HTTPS within the file cache should you close them (presuming it's sensitive content that should not be continued disk), so that you wouldn't enjoy the browser's cache and would need to reload this content.