An Alerting Service (AS) informs its clients about new information provided by several suppliers. Special interests of clients can be defined as profiles. In the context of digital libraries, suppliers are the providers of documents. Providers are typically scientific publishers. In this paper we assume, that the providers are known to the clients. A general model and architecture of an Alerting Service is given in [1]. Channel technology has been developed for broadcast of news and continous streams of data like stock rates. For the digital library enviroment a finer granularity in profile definition than for common broadcasting is needed. In contrast to broadcast services, publishing events of multiple providers have to be presented to each client in a uniform way. In this summary we evaluate how the two competing approaches of Channel technology, Netscape’s Netcaster [3] and Microsofts Active Channels [2] meet these requirements. To satisfy user’s needs events have to be filtered by more or less complex profiles, e. g. a set of documents (like journals), a list of keywords (selected arbitraryly or from a thesaurus) or a query in a full-fledged query language like STARTS [4]. An easy-to-use and powerful profile definition language is one requirement for an AS. The second is a unified view, that means splitting the n:m-relationship between providers and clients. The use of both technologies strongly depends on how the contents is to be filtered, i.e. how the user profile is to be defined.