Earlier today we turned on code to change how we do authentication and turned off SSL on your dashboards. The main change you should notice is that things on the backend of your blog, such as your Presentation and Write page, should load significantly faster than they used to.
Why? When WordPress first started we thought having everything in the dashboard be over SSL would be pretty cool, but it ended up causing a ton of problems. If there were any external images or embeds called it would cause mixed content warnings for IE users, it caused a big load on our web servers and later load balancers, made it difficult to integrate with external partners, but most importantly it really slowed the dashboard down.
You can read about how SSL works on Wikipedia, but basically it slowed down every connection while it negotiated the secure bits and broke caching in a lot of clients.
We recognize that some people might value the security of SSL for their blog over the speed, so we’re going to try to make it an option at some point in the future. For now, enjoy the faster writing and editing on your blog.