WebDAV is a suite of protocol extensions to hypertext transfer protocol (HTTP) 1.1, for the management of resource properties, the creation and management of resource collections, namespace manipulation, and resource locking. The WebDAV core protocol enables users to create, modify, and delete resources or collections on a WebDAV server.

This two-page paper briefly reports on the architecture and the development of the hypertext annotation and trail system (HATS), based on WebDAV. HATS provides annotation editing, deleting, searching, and sharing using the capabilities of the WebDAV server, and supports the storage and visualization of hyper-trails, while existing systems do not keep track of the path of users through the Web, or do not support annotations. The paper also briefly compares HATS with existing Web annotation systems, and discusses the advantages of using WebDAV as an annotation server. HATS is very helpful for users, in the sense that it allows them to find previously visited Web pages, and to determine how they got there, using the standard WebDAV protocol. HATS can be used for any resource that has a uniform resource locator (URL), including Web pages, portable document format (PDF) files, multimedia files, and images.

The paper is clear, well written, and well structured. It addresses an important topic. However, its two-page length only allows for a high-level description of the system, making the paper less useful for readers. Besides the lack of implementation details, no information is given about how a potential user can get HATS.