I find this bookmark site useful for saving links for late sharing of source information and as a general reference. My biggest complaint is that when a site like YT deletes a video it also gets deleted here. This site also keeps track of you by installing folders within your own, the content of which is not accessible by you.

очень интересное расширение

Requires a monthly subscription to save information privately. Does not make this outright clear enough until after account creation. Do not recommend unless you're okay with your bookmarks being public.

Pearltrees extension worked great until Firefox 78. Since it's been 3 years since the last extension update, it's time for Pearltrees to do a little maintenance and fix it for their paid subscribers.

Super

Bookmarking Is Tomorrows Memory, Alibi and teacher.

very good