The shift towards communicative language teaching in recent decades has created pressure towards individualized pedagogy that arises from the diversity found within any group of learners. One of the richest areas of diversity in target language needs across learners is the lexis of the various discourse communities that different learners are attempting to enter. This paper elucidates one way that the Web and the new practices that it has engendered has created possibilities for individualizing vocabulary learning in context and for doing this incidentally and in real time. We propose an approach to individualization that leverages the navigation level of the Web. This approach is illustrated with a browser-based agent that first detects collocations incidentally within the web pages that the user freely browses, and then unobtrusively offers to bring these to the learner's attention. The novel challenge for the technology was that the natural language processing techniques must perform reliably in real time, in unscripted noisy contexts. Two empirical studies are reported. One shows that the tool enhances collocation learning and the other that unrestricted learners using the tool encounter divergent sets of collocations, resulting in individualization.