“A pattern ... describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over” [1]. The possible benefits of using design patterns for Web applications are clear. They help fill the gap between requirements specification and conceptual modeling. They support conceptual modeling-by-reuse, i.e. design by adapting and combining already-proven solutions to new problems. They support conceptual modeling-in-the-very-large, i.e. the specification of the general features of an application, ignoring the details. This paper describes relevant issues about design patterns for the Web and illustrates an initiative of ACM SIGWEB (the ACM Special Interest Group on Hypertext, Hypermedia, and the Web). The initiative aims, with the contribution of researchers and professionals of different communities, to build an on-line repository for Web design patterns.