Nice catch about the primary tag being included in the URL! Although that's not true for all interfaces, but still great for SEO, since I was talking about that yesterday.
Also the primary tag is the only one displayed on the posts thumbnails, on some interfaces.
Yeah I know, and I am not a fan of that behavior, I want to set the tags myself.
Ah, you're talking about interfaces which set their own tags as primary tags, if they are not already added. I would make this optional, or at least not set them as primary tags unless they were set by the author.
I was referring to something of visual nature. That the primary tag is the only one displayed on the the post thumbnail, in your feed, on most interfaces.
👍😀♨