A First Approach to Build Product Lines of Multi-organizational Web Based Systems (MOWS) ⋆ David Benavides 1 , Antonio Ruiz-Cort´ es 1 , Miguel A. Serrano 2 , and Carlos Montes de Oca V´ azquez 2 1 Departamento de Lenguajes y Sistemas Inform´ aticos, E.T.S.Ingenieros Inform´ aticos, Universidad de Sevilla, Avda. ReinaMercedes s/n, 41012 Sevilla, Espa˜ na benavides@us.es, aruiz@lsi.us.es 2 Centro de Investigaci´ on en Matem´ aticas AP 402, Guanajuato, Gto., CP 36000, M´ exico {masv,moca}@cimat.mx Abstract. From the recent past and current state of the Internet, it is possible to forecast a wide growing of Multi Organizational Web–based Systems (MOWS). Therefore, the reduction of both costs and time–to–market is desirable. On the other hand, the success of building software in Product Lines (PL) is being demon- strated in different contexts reducing both time–to–market and costs. However, research on PL topics has not been oriented to include web–based assets. In this article, we propose a first approach to use PL methodologies to build MOWS. We identify quality aspects as a key point when building Product Lines of MOWS and we give a way to specify quality aspects in PL. 1 Introduction The term “Product Line" (PL) was first introduced in 1976 by David Parnas [13] and it has been widely studied in Universities and in the industry since then [12,16]. The PL concept means that similar products share a common set of components and functionality (called core assets) and still, each individual product have some functionality specific to it (variable part). For the software industry, it is a good approach since similar parts (e.g. those belonging to the core assets) are developed only once and reused since then. The goal for organizations that follow a PL development approach is to be able to develop their products, by developing the variable parts only, and not developing the whole product. MOWS have been described in [14] as a particular case of federated systems [1] or work–flows with multiple organizations [7]. The main difference between federated systems and MOWS is that in federated systems providers are often reduced in number, known beforehand and do not change along the system life–cycle. In MOWS, providers are numerous, they are not necessarily known a priori and they can change along the system life–cycle. ⋆ This work was partially funded by the Spanish Ministry of Science and Technology under grant TIC2003-02737-C02-01 (WEBMADE)