In this paper, we present a framework for context-based awareness support designed for web-based groupware systems. Nowadays, such systems can be accessed through web-enabled mobile devices, such as PDAs and cellular phones, which allow their users to perform simple tasks, such as contacting colleagues or reading messages. However, these devices present some constraints related to their intrinsic characteristics (reduced display size, limited memory capacity...). These constraints make more acute the need for information filtering. We present a framework for awareness support which is able to adapt the awareness information to the user's context, in order to reduce the risk of information overload. This framework, called BW-M, selects among the available awareness information that which matches the user's, represented through pre-defined profiles, according her/his current context.