Raindrop.io

Raindrop.io is an all-in-one bookmark manager that allows users to save, organize, and share web content. It provides features like instant previews, collection and tag-based organization, full-text search, and permanent copies of saved pages. The service is available across multiple platforms and offers both free and paid plans.

Raindrop.io is a comprehensive bookmark manager that aligns very well with the URList concept. It offers core features like URL saving with instant previews, robust organization into collections (lists) and tags (sections), and public sharing of collections. While it doesn't explicitly mention 'Tufte-style side notes,' it does offer 'Highlights' for annotation, which serves a similar contextual purpose. The interface is clean and focused on content, and it supports various media types. It also provides user profiles, authentication, granular sharing, mobile responsiveness, and embed support.