Referential expressions are used to introduce and continue reference to entities with particular referential properties, but also with particular discourse properties. In this paper we investigate the referential and discourse properties of pe-marked indefinite direct objects in Romanian, which are an instance of Diff erential Object Marking (DOM). Pe-marking is generally obligatory for definite noun phrases but optional for indefinite ones. The optionality of pe marking with indefinite descriptions constitutes the focus of the present article. We will show that, on the one hand, pe with indefinite descriptions allows the realization of referential properties such as specific or wide scope readings, but that on the other hand, pe also signals discourse prominence, in particular in such contexts where referential properties are neutralized. We assume three parameters for discourse prominence, namely referential persistence, the topic-shift potential and the type of anaphoric referring expressions. We used these three parameters in a web-based story continuation experiment. The findings of the experiment revealed several interesting patterns: (i) that pe -marked direct objects are referentially more persistent than their unmarked counterparts, (ii) that pe -marked direct objects show a systematic preference to become topics two or three sentences after being introduced in the discourse, and (iii) that (modified) definite NPs were chosen to refer back to the referent of the marked as well as to the referent of the unmarked direct object. On the basis of the first two parameters we conclude that the relevant discourse contribution of pe is to signal to the hearer that subsequent information about that referent will follow, whereas the third parameter indicates that the referent of the pe -marked indefinite is not necessarily associated with a high level of activation. The general findings of the experiment support Kehler et al.'s (2008) intuition to differentiate between referential persistence and the activation level of the referent.