Activity states framework is a communication analysis that applies cognition theories (situated cognition, activity theory) to make sense of communication activities during mediated cross-domain collaboration. Mediated cross-domain collaboration is where different experts use Web media (instant messaging) to collaborate together. This results in emerging practices among them making it crucial to identify those practices for building relevant tools. However the challenge is to make sense of their communications because mediated communications are asynchronous making it challenging to identify: who said what to whom and what are they doing? Activity states was developed to organize the communications for making sense the experts emerging practices. It uses cognition concepts (e.g. conceptualization) to help design a computer program so that it can know what to look for, and what to do next. We outline the challenges and limitations of present concepts when applied to cross- domain collaboration in the real world.