In fact I took your topmost entry with no helpful site/update tags and dove in a little to try to understand why a RSS friendly blogger might not be passing along ~ tags for better reader discovery.

Turns out my scarce info test case blogger has a mastodon that immediately lists all these tags about himself [I've stripped it down] ...

#FrontEnd Developer #CSS #Halifax #London #Singapore Technical writer and rabbit-hole deep-diver Former Organiser for https://londonwebstandards.org & https://stateofthebrowser.com Interests: #Bushcraft #Outdoors #DnD #Fantasy #SciFi #HipHop #CSS #Eleventy #IndieWeb #OpenSource #OpenWeb

I conclude if he knew such site and post tags getting to RSS would be of use, he'd probably make the tiny effort to wire the descriptions.

Nonetheless I merely crawled links for a minute to found this info, so I imagine something like the free tier of the Cloudflare crawling api might suffice over time for a simplistic automated fix to hint decorate blog sites.

I mean, given that we're not trying to recreate pagerank, but just trying to tip the balance in favor of desirable initial discovery.

Crawling related sites for tags could work (open graph tags on the website are another good source). I'm wary of mixing data across contexts though. A blog and a Mastodon profile may intend to present a different face to the world or could discuss different topics.