I'm a bit concerned as my address bar has an exclamation mark in a circle and it's stating Not Secure when I'm on the site, what does that mean?
For a different take...
The connection is an insecure http one rather than an encrypted http one. This means your data could be intercepted and read by third parties. It’s up to you to assess but the greatest risks might be where you make financial transactions and I wouldn’t use bank or online shopping at all without a secure connection.
A forum probably carries less risk but bear in mind you are posting personal information even if it’s only log in details. Some will suggest that all sites should be https to make it harder for the governments, etc, to monitor...
Another consideration is where you are connecting from. Your home LAN is safer than an open wifi hotspot…
I notice that this forum does offer a https connection but there is a warning for the SSL certificate (needed for https) . It’s possibly something to do with a certificate being shared over a few of the host IPs pages rather than a dedicated one or something along those. It’s probably best to let Ian or someone clarify this situation.