CiteULike

CiteULike was a foundational web-based service established to assist academics in organizing their scholarly papers. Technically, it operated as a social bookmarking system specifically for academic citations, utilizing a folksonomy-based tagging architecture. It was notable for its ability to automatically extract citation metadata from various websites (like PubMed, arXiv, and Amazon) and generate formatted BibTeX or RIS files. In the 2026 market landscape, CiteULike is positioned as a legacy reference case; the service officially ceased operations on March 30, 2019. Its historical importance lies in its early implementation of collaborative filtering for article recommendations—an approach now standard in AI-driven platforms like Semantic Scholar. While no longer a live SaaS entity, its data and architectural philosophy influenced modern open-source citation tools. For researchers in 2026, it serves as a benchmark for lightweight, community-driven metadata management, though its absence has shifted the market toward integrated AI assistants and robust commercial platforms like Mendeley and Zotero.