I use zotero to manage literature reviews and citations. But it is frustrating how the web version (I won’t install the desktop version) sucks at importing content. The magic add works for many sites and papers, but not all. The fact that it can’t import a citation is so annoying that I’ll probably drop the tool and use endnote that sucks so much more, but at least works consistently.
You are really missing the magic if you don't use the desktop app. It syncs across devices and web as well (through their servers or yours with webdav)