We describe an expert evaluation for user requirement elicitation of an annotation system - The Digital Library Annotation Service, DiLAS, that facilitates collaborative information access and sharing. An analytical evaluation was conducted as a Participatory Group Evaluation, which involved presentation beyond the written papers of the objectives and rationale behind the development of the prototype. The empirical evaluation of DiLAS consisted of two experiments. The first evaluation experiment was a bottom up evaluation of the usability of the interface using a qualitative approach. The second stage of our evaluation moved towards a broader work context with a User and Work Centred Evaluation involving an entire, collaborative task situation, which required knowledge sharing on a common real life work task. This paper describes a first evaluation stage in an iterative evaluation process, and the preliminary result is a set of requirements that will inform the next stage of the DiLAS.