I have just discovered feedle - a search engine for RSS feeds. Look for what’s interesting to you. My search for #Obsidian information led me here. https://feedle.world
1) Brilliant idea!
2) Every mastodon account has an rss feed so hypothetically could be indexed by this search engine. Eg feedl's own mastodon account is has RSS feed (just like everyone else does)
https://mastodon.social/@feedle.rss
3) "every search in feedle has its dedicated RSS feed."