Qiqqa is by far the strongest solution for research and managing pdf's. Zotero, named as a comparison is weak as it does not allow pdf;s to be loaded into its interface - you need to use a pdf reader, which defeats its whole purpose. With Qiqqa documents in a library can be searched together. It has excellent maps of your libraries. It is not prefect, having a few glitches, but still is the only one of its kind.
Based on our record, Tagpacker seems to be more popular. It has been mentiond 2 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Currently, I use Tagpacker, which is a terrible name but a very useful bookmarking site with a really excellent tagging extension that uses tag bundles (tagpacks) to make it so that you can just click right down the list and make sure you don't forget anything. I have a bunch of tag bundles: Availability, Genre, Pairing, Theme, Opinion, Author, Reader, and Series. I don't know what your setup is like, but it... Source: over 1 year ago
I have been using this https://tagpacker.com. - Source: Hacker News / almost 2 years ago
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Pocket - When you find something you want to view later, put it in Pocket.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .