It would be useful to know what happens with the users who click through but unfortunately, I've never had any joy locating the owner of steemit.com's analytics account so the knowledge of seeing if new users register or simply bounce back out (at the cost of $0.05) is unavailable to us.

Lots of people have experimented with SEO over the years. It's not really something that I've paid much attention to, but the best tips I remember were these: How To Properly Embed YouTube Videos Into Your Steemit Article And Make Views Count In Your YT Channel [tutorial] & Steemit SEO Guide - How to rank on Google. No idea how relevant they are after all this time, though. I don't remember ever reading anything definitive about exclusion/inclusion of communities in the path.

I do know that from a functional perspective it doesn't matter what you put in that "first tag" field of the URL (if anything). Anything works: https://steemit.com/kilroy_was_here/@sporting-gorilla/real-madrid-v-chelsea-predicted-lineups - https://steemit.com/@sporting-gorilla/real-madrid-v-chelsea-predicted-lineups. I've always been content to let Steemit worry about the SEO stuff. It gives me a headache. ;-)