This forum has been running under SSL (https://) for a while now. You may notice that some browsers will tell you that insecure content is being automatically blocked. I'm not sure what it's looking at. There were a handful of http: links (<a> tag) on the page, which I changed to https:, but as far as I can tell, there are no images, CSS files, JS files, etc. using http:. If there are any, they must be inside an https-protected link (which I probably can't get to). So, what browsers are complaining about, I'm not sure. Links to non-SSL pages should not generate such a warning, but who knows. I hope that they are not blindly scanning the page source for http:, even if it's in a posting's text!
One thing that can cause bona fide warnings is user avatars that use a link to your own site, and you are still using http: on them instead of https:. If you have SSL on your site, please modify your avatar and signature blocks to use https: if possible. If you post a link to another page, please use https: if at all possible. It looks better if a browser isn't complaining that content is insecure.