This exploratory study examines corrective feedback in native speaker-nonnative speaker (NS-NNS) and NNS-NNS dyads while participants were engaged in communicative and problem-solving activities via "Yahoo! Instant Messenger" (YIM). As "negotiation of meaning" studies of the 1990s have shown, linguistic items which learners negotiate in face-to-face (F2F) interaction seem to facilitate their L2 development. This type of research has been successfully extended to computer-mediated contexts. Recently, findings from second language acquisition (SLA)-motivated research have shown that negative evidence or incidental focus-on-form in communicative classrooms appears to encourage learner awareness that often leads to successful uptake. Six research questions are addressed in this study. They include the availability of error correction episodes in NS-NNS and NNS-NNS online dyad work, type of corrective feedback provided to L2 learners, category of errors, learner uptake or response, type of uptake, and length of moves. Among the results of this exploratory study we find the following: error correction episodes are available in an instant messaging context and, in this context, more indirect corrective feedback that focuses primarily on grammatical and lexical errors is provided to L2 learners. Also, simple moves characterize these YIM error correction episodes, and there is evidence of successful learner uptake. (Contains 3 figures, 3 tables and 5 notes.)