Learning

Most recommended

• WikipediaA free, volunteer-built, downloadable encyclopedia with sourcing rules and open moderation that's invaluable as a starting point, though critics say contentious political topics are biased or manipulated.404recommend
• AnkiAn open-source flashcard app whose spaced repetition scheduling reliably drills vocabulary and facts into memory; critics find setup and settings complicated and the paid iOS app pricey.136recommend
• LobstersAn invite-only, HN-like tech forum with tag filters (including for AI content), stronger moderation and more technical, less startup-focused discussion; critics cite hard joining, groupthink and heavy-handed moderation.105recommend
• 3Blue1BrownA math video channel whose visualizations make math concepts, including neural networks, intuitive and beautiful, though critics say viewers retain little without rigor, exercises or structure.96recommend
• ArchWikiClear, accurate, concise documentation praised as one of the best Linux references, and useful far beyond Arch. Critics say some pages are bare or outdated.86recommend
• arXivPeople recommend it as the free, fast place to read and publish preprints, often ahead of journal versions, with timestamps and stable IDs. Critics note that anyone can post almost anything with little content review.83recommend
• ScratchPeople recommend Scratch as a gentle, block-based way for children to learn programming concepts without syntax, and many say it sparked their lasting interest in computing. Critics say it becomes hard to navigate as projects grow and has a low ceiling.69recommend
• Khan AcademyFree, clear lessons people use to fill math gaps and supplement school. Critics find the videos slow and repetitive and say results depend on consistent practice.67recommend
• Wayback MachinePeople recommend it as a free library of the web that preserves pages, including dead sites, that would otherwise be lost. Critics say it is slow, rate-limits heavily, and sometimes removes content.57recommend
• LWN.net subscriptionPeople recommend LWN for high-quality, non-sensational technical journalism on Linux and open source, and many say it is worth paying for. The most common caveat is the price, with some finding it high for the value.53recommend
• GrokipediaRecommended as a comprehensive, easy-to-correct alternative to Wikipedia. Most common caveat: critics call it ideologically biased and prone to errors.52recommend
• iNaturalistFree app and website for identifying and recording wildlife, with community experts confirming IDs; critics find location privacy hard to find and the interface confusing.52recommend
• LeetCodePeople recommend it for practicing the algorithm problems used in technical interviews, and say the free version is enough for standard interviews. The most common caveat is that critics say it rewards interview tricks more than real engineering.50recommend
• Sheldon Brown's Bicycle Technical InfoA free, long-running bicycle repair and wheelbuilding reference by Sheldon Brown, praised for generous, practical information that helps people fix their own bikes.49recommend
• GPU building gameTeaches digital logic through hands-on wiring of gates into GPU parts, though critics say it assumes prior circuit knowledge and explains some steps poorly.49recommend
• Logo programming languageRecommended for being interactive, graphical and simple, making it a gentle first language for learning to program. Main caveat: some find it ambiguous and limited to turtle graphics.45recommend
• Project EulerRecommended for math-and-code puzzles that reward deep thinking and show how others solved them. Caveat: later problems need heavy math, and explanations are thin.45recommend
• Local WikipediaShows Wikipedia articles near your location, which people enjoy for discovering local history. Critics say the radius is not really a half-hour walk and results are thin outside large English-speaking areas.45recommend
• Texas Instruments TI-84 EvoLong-lasting graphing calculator that students use through school and college for plotting, programming and arithmetic. Most common caveat: it costs too much for what it offers.41recommend
• Dolly Parton's Imagination LibraryFree monthly age-appropriate books mailed to children from birth to age 5, addressed in each child's name, and widely praised for its reach and its legacy.41recommend
• DuolingoRecommended for building basic vocabulary, grammar exposure and a guided path for beginners; critics say it gamifies rather than teaching conversational fluency.39recommend
• microgpt by Andrej KarpathyRecommended as a tiny, readable GPT in pure Python that shows the whole training pipeline end-to-end. Caveat: some find the accompanying site assumes too much prior knowledge.37recommend
• Quanta MagazineReaders praise its clear, careful science and math writing, which is free and ad-free. Critics say headlines oversell articles and some pieces are hard to follow.36recommend
• Math AcademyPeople recommend it for a structured, distraction-free path through math with diagnosed gaps and many practice problems. The most common caveat is that the explanations are often too thin.35recommend
• Piano by ear memory gameA fun, simple Simon-style game for practicing playing piano by ear, especially useful for beginners. Critics say the wrong-note feedback feels punitive and the interface feels unpolished.35recommend
• Wikipedia: Signs of AI writingA free Wikipedia guide to common patterns in LLM-written text, praised for going well beyond the em-dash rule. Some say it is fallible in the long run.34recommend
• Recurse CenterRecommended as a self-directed programming community that builds lasting friendships and shapes careers.34recommend
• KiwixFree reader that serves Wikipedia and other sites offline for search and reading. Caveats: weak search, and Wikipedia copies can't be updated incrementally.33recommend
• ciechanow.skiInteractive articles that explain how mechanical and physical things work, praised for visual craft, accuracy and readable code.33recommend
• Nand2TetrisPeople recommend it as a hands-on way to learn how computers work, from logic gates up to compilers. Critics note it skips microcode.31recommend