Quorum75 is a field index of the web — a structured directory that catalogues 858 active web properties across 22 subject areas. The project began as a straightforward observation exercise: documenting what exists, where it sits in the web's ecosystem, and how it relates to adjacent entries. The result is a cross-sector reference that spans everything from dental clinics and law firms to wagering platforms and independent media producers. The index is organised by subject rather than by geography or language. Each of the 22 sections represents a distinct field of observation, from the densely populated Wagering & Online Games section to the more specialised corners of the catalogue, such as Official Records & Permits or Land, Property & Letting. This structure makes it straightforward to locate clusters of related operators, or to browse across sectors when the subject of interest cuts across conventional industry lines. Entries in Quorum75 are submitted by site owners and reviewed before publication. The directory does not rank or score its entries — each site appears once, in the section that best fits its primary subject matter. The index includes commercial services, community platforms, informational sites, and specialist operators across multiple countries. Quorum75 is free to use and free to list in. Site owners can submit a web property using the form on this site; submissions are reviewed and, if approved, added to the relevant section. The index is updated regularly as new submissions are processed. The field notebook approach that guides Quorum75 is a simple one: observe, classify, and record. The web is a large and varied place, and a well-maintained index remains a useful tool for anyone trying to navigate it systematically.