Readwise Reader
read.readwise.io
A unified reading app that brings together articles, newsletters, PDFs, ebooks, and Twitter threads with highlighting, annotations, and spaced-repetition review.
Why it is useful
Solves the fragmented reading problem by pulling all saved content into one interface with consistent annotation tools. The spaced-repetition review of highlights is genuinely useful for retaining what you read, rather than passively saving links that never get reviewed. The integration with Readwise's flashcard system makes it the strongest tool available for building a reading-to-retention workflow.