This paper takes a close look at the syntactic, prosodic, semantic, distributional and functional properties of the phrase "I mean". Based on data drawn from private conversations and radio phone-ins, instances of "I mean" are analyzed according to their textual and interpersonal functions in interactional settings. The main functions "I mean" carries out are concerned with the organization of the textual structure of utterances: parenthetical asides, show concessions, concessive repairs, conclusions or quotations can be marked and made accessible for the interactants. Interpersonal functions are less common and include the marking of stretches of "disfluent talk" ("Disfluenzen") or changes of perspectives. These findings are then interpreted within the framework of Construction Grammar. Such a framework can be used to highlight and systematize the connections of "I mean" to related schematic constructions such as "discourse marker" or "complement-taking verb". Furthermore, it provides a model on which hypotheses concerning grammaticalization processes can be tested.