Digital participation platforms (DPP) are websites initiated by local governments through which citizens can post and react to ideas for their city. In practice, the majority of DPP users browse the posted ideas without contributing any. This activity, referred to as lurking, has widely recognized positive outcomes, especially in a citizen participation context. However, it has been devoted little attention. In practice, the idea browsing features available on current DPP are limited, and the literature has not evaluated the available approaches nor studied the requirements for idea browsing. In this paper, we report on an evaluation of the filterable list, which is the most common idea browsing approach on DPP. Our findings show that it lacks stimulation hedonic quality and call for a more stimulating approach. Thus, we conducted 11 semi-structured interviews to collect requirements and found that idea browsing on DPP should be supported by the combination of (1) a stimulating interactive representation such as circle packing or thematic trees displayed as entry point and (2) a filterable list for deeper exploration. This article is the first to study requirements for idea browsing features on DPP.