I read an interesting post by Juha-Matti Santala (a new addition to my feed collection) on linking to books online. He had complained on Mastodon about the lack of Mastodon alternatives, but was heartened when he received recommendations for Bookwyrm (a Fediverse Goodreads alternative), Open Library (an Internet Archive project), bookshop.org (an online store for physical books), and The Storygraph (I understand it to be a Goodreads alternative). The vast majority of books I have written about thus far are available on Project Gutenberg, so I have not had too many book link issues. Open Library would be my pick for the best Amazon/Goodreads alternative for linking to books online, but I will throw in two additional ideas. LibraryThing, which is somewhat similar to Goodreads but with a greater emphasis on cataloging, is another acceptable source. Inventaire is a free and open source platform for cataloging physical books.