Glasp

Sweet spot: an individual researcher, student, writer, or curious heavy reader who wants every highlight from every source in one searchable library and is willing to pay $10/mo for the AI features once they are hooked. Glasp's biggest virtue is that it is genuinely easy — install the extension, highlight as you read, and the library builds itself. Failure modes. If you already use Readwise + Reader, Glasp's feature set is largely overlapping and you should not switch unless the social discovery or YouTube-summary depth specifically pulls you. The "AI clone" is a clever feature but the quality scales with how much you have highlighted — new users get a thin assistant. Privacy-strict users should note that public highlights are the default; you must upgrade to Pro for private mode. What to pilot. Install the extension, use Glasp as your only highlighter for two weeks across web, PDF, and YouTube. At the end, search your library for a topic you read about and see whether the right highlights surface. If they do, the lock-in starts there; if not, your usage was probably too thin and either Readwise or just bookmarking is fine.

Glasp is a browser extension and web app that lets you highlight passages on any webpage, PDF, or YouTube transcript and saves them to a personal collection that is searchable across everything you have ever marked. Think of it as Kindle highlights for the entire internet, with a social layer on top: you can follow other users, see what they are highlighting, and discover content through their reading trails. The AI layer added over the last two years is the reason it shows up in tool directories now. Glasp generates AI summaries of YouTube videos (using ChatGPT, Claude, Gemini, or Mistral as the user picks), AI summaries of webpages and PDFs grounded in your highlights, and an "AI clone" feature that builds a personalised assistant trained on your highlights and notes — useful for researchers and writers who want their reading history to be queryable. It is free for the basic tier (unlimited public highlights, ~100 YouTube summaries/month, basic PDF support), with a Pro tier around $10/mo (annually) that adds private highlights, advanced summary models, larger PDF and audio quotas, and more storage. The product is well-loved by a niche of researchers, students, and content creators — not a mass-market tool, but very sticky for the audience it serves.