Three groups of 20 dyads planned the MTV Music Video Awards Show over computers.  The groups varied in whether they could send 4-line, 10-line, or 18-line messages, in part to examine whether increased planning efficiency in computer- mediated communication reflects communication strategies associated with constraints on message size.  The results demonstrate that increased efficiency is not a function of such design features as the maximum message that may be sent.  However, the subjects  in the 4-line condition sent shorter messages to one another, were less likely to engage in a strategy of making multiple suggestions that required a single assent, and were more likely to differ in the relative proportion of their contributions to the discourse.  The subjects  in the 10-line condition had shorter maximum messages (and proportionately more disfluencies) than those in the 18-line condition, despite the finding that the maximum messages of the latter would have also fit within 10 lines.  Thus, the results also support a claim that size of the text window may result in different discourse management strategies, and may influence an initial discourse planning stage.