You can access the full abstract and potentially the full text through these scholarly platforms: ResearchGate My favorites (bookmarks) schema - ACM Digital Library
Physical books are read sequentially. A bookmark preserves a single location within a fixed, linear structure (page number). It operates on a —"I stopped at the bottom of the left column on page 142." There is no inherent mechanism for cross-referencing multiple stopping points within the same book without multiple bookmarks. bookmarks and favorites
Technically, they serve the same purpose: saving a URL for quick access later. The difference is mostly branding: You can access the full abstract and potentially