[Context/Motivation] In crowd requirements engineering, users are asked specific questions (explicit pull feedback) to elicit requirements. Existing approaches collect explicit pull feedback by asking the same questions to all users. [Problem] Not all questions are meaningful for all users, e.g. regarding a functionality they have not yet used. Furthermore, without knowing the user behaviour giving rise to the feedback, it is difficult to understand the reasons for the feedback. These reasons are important for deriving requirements. [Principal ideas] Our idea is to use the user behaviour (implicit feedback) to adapt the collection of explicit pull feedback and the derivation of requirements. We embed this novel collection of explicit pull feedback into an approach with a rich palette of elements from crowd-based requirements engineering to motivate user participation and to support requirements derivation. [Contribution]. To our best knowledge, this is the first approach that makes use of implicit feedback to individually adapt the collection of explicit pull feedback to the user. We sketch our approach and our research and evaluation plan regarding the application of the approach in the context of the interdisciplinary and large-scale research project SMART-AGE with around 500 users.