we have a weird situation right now with different web sites presenting different canonical URLs. I wonder which one wins and how that effects SEO scores.

I'm glad you like it! Steemitdev has 'noindex' set which might help with that although I'm not 100% sure. steemitdev should really have a robots.txt file that tells all bots to go away, but it doesn't.

Hopefully, it's only temporary. I've tested all of the changes and they look good. I've committed a change to remove the comments which I'll get deployed before approving - but this shouldn't impact anything!

It would be good if the main pages had a link to it, too (and also /promoted).

With the /tags, there's no obvious place in the siite structure for this to live at the moment. Which in my opinion, is ok - a page that simply has Trending tags doesn't really offer much. The main reason that I fixed it is so that I can use the idea contextually elsewhere - specifically on the "All Posts" feed. I don't feel particularly strongly on this point so if you have any suggestions as to where it would logically fit, I'm listening.

Minor typo here. Should be "steemitdev".

Thanks - I've updated the post.