Threshold99 is a curated web directory built to function as a reliable reference archive. The index holds 832 reviewed sites organised across 22 subject collections, each covering a defined area of the web — from healthcare and legal services to technology platforms and travel operators. Entries in Threshold99 are submitted by site operators and reviewed before they are admitted to the catalogue. The review is straightforward: the submitted site must be active, reachable, and relevant to its selected collection. Once approved, an entry is filed and held in the archive at no charge. The directory is arranged for practical use. Each collection can be browsed independently, and recently added entries appear on the home page so returning visitors can see what has been filed since their last visit. The archive does not rank entries by traffic or engagement — all admitted sites are held as equal records. Threshold99 accepts submissions from operators running active websites across any of the 22 collections. The process is free and straightforward: submit a site address, select the appropriate collection, and the editorial team will review the entry within a few business days. The archive is maintained continuously. Sites that remain active are held in the catalogue; updates can be submitted through the standard form at any time. Threshold99 is not affiliated with any listed site and does not accept payment for placement or priority consideration.