I've been using Ian's Secure Shoelace Knot for... years? I can't even remember how long, but it's served me very well. I just love how much more secure it is and how symmetrical and balanced the final result is. It's also such a trivial upgrade for kids that have learned to tie their shoes using the "bunny ear" method... just one extra twist.
I forgot to add a link to our recent announcement blog post to the project README. I've added that now, and I think it may help explain why we specifically built a service like this on top of Tailscale to take advantage of Magic DNS, automatically authenticated connections, etc. https://tailscale.com/blog/golink/
UX definitely ended up being one of the hardest parts. We also never got to the point of really building a compelling product on top of the protocols. We did actually do some work on privacy though, but it never got super far. For example, you could set simple access controls on content that was only available to friends that logged in with an OpenID. I think I had it so that certain of your hcard attributes were only included for authenticated users as well.
Some of the work we did then still exists today in various forms. Activity Steams led to Activity Pub, which has seen far more adoption than we ever did.
And microformats are still widely used in some communities, though certainly not like it could have been, largely things to Google putting weight behind schema.org. For example, nearly all of the indieweb.org work is based around microformats at the core, with things like webmention, micropub, etc
https://www.fieggen.com/shoelace/secureknot.htm
And like many things on HN, previous discussion: https://news.ycombinator.com/item?id=13399095