Apparently LinkedIn.com let their SSL certificate expire this morning. Assuming they really let it expire, this is a big oops. Hopefully, someone in their Production Operations Group has been alerted to the problem and is working on getting a new one.

The screenshot is from Firefox 3. In the old days, Firefox or Netscape used a frustrating pop-up for the user to choose how to handle security certificates which were not properly signed or expired. My first time, it took three readings to make sure I was doing the right thing. Even on my hundredth time, I wasn’t sure I was doing the right thing.

It’s a new day, I guess. Now, a page similar to the handling of HTTP error codes is shown. Useful facts? Good. Plain language? Excellent.