I browsed a few random sites[1][2][3] from https://search.marginalia.nu/explore/random - it's a nice way to preview many random things. Bookmarked. Seeing these interesting sites makes me wish I could RSS-subscribe to them (or add them on social media, ironically).
[2] https://annotations.lindylearn.io/ - A collaborative social layer for annotating all webpages. Something I've thought about over the years, and finally run across.
[3] https://fed.brid.gy/ - Connects a website to Mastodon/the fediverse, with two-way post flow.