I am confused about my profiles for the trailhead and my developer account.  When I am on the Discussion Forums or working in Trailhead, I see in the upper right corner my picture and the name “Blair Sellke 2”.  But when I log into my developer account I see “BlairD Sellke”.  Do I have 2 profile accounts?
 

For Partner Communities - It there a feature like the free Chatter External for Salesforce, where a non-partner user or salesforce user can access the "Discussions & Groups" on the Partner Community site for free and not have access to anything else?

I am confused about my profiles for the trailhead and my developer account.  When I am on the Discussion Forums or working in Trailhead, I see in the upper right corner my picture and the name “Blair Sellke 2”.  But when I log into my developer account I see “BlairD Sellke”.  Do I have 2 profile accounts?