When comparing WorldBrain's Memex vs Hypothesis, the Slant community recommends Hypothesis for most people. In the question“What are the best web annotation tools?” Hypothesis is ranked 1st while WorldBrain's Memex is ranked 6th. The most important reason people chose Hypothesis is:
Hypothesis is completely free and open source, its source code is hosted in GitHub.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open Source
MIT License
Pro Import
From Pocket, Diigo, Raindrop.io, browser, HTML files.
Pro Offline-first
Pro Open Source
Hypothesis is completely free and open source, its source code is hosted in GitHub.
Pro Everything can be searched through
Searchable stream of annotations, replies, and email notifications.
Pro Private or public
You can work in private groups and then publish, keep annotations private, or make it public from scratch.
Pro Tags
You can sort by tags, which makes it far more powerful.
Pro Lets you see public & private annotations on that webpage
Helpful to see what people thought or see useful references they might have left. Useful for group collaborations as well (research groups, book clubs, class study groups, etc)
Pro Chrome browser extension works on Brave browser
Most (maybe all) Chromium-based browsers let you use Chrome browser extensions.
Pro Chrome browser extension
Has browser extension for Chrome, which makes the job of annotating web pages even easier.
Pro Unique URLs for each annotation
You can link directly to an annotation.
Cons
Con Buggy
Sometimes hangs, sometimes ignores non-essential commands. But at least highlighting/annotations are stable.
Con No browser extensions apart from Chrome
Allegedly, one can use bookmarklet instead, but in Firefox it works only for some of websites.
Con Seems under development
Too many rough edges and/or bugs as you use it. For example, you have to keep logging in every time you want to add a page using the chrome extension. There are ways to add annotations on the mobile too, but way too buggy. Hopefully they fix these problems soon. Very good idea; poorly implemented.