Scientific workflows have been introduced to enhance reproducibility, sharing and reuse of in-silico experiments. Faced with increasing numbers of workflows available in public repositories, users have a crucial need for assistance in workflow discovery. Identifying the functional elements shared between workflows and thus determining similarity between workflows is then a key point. In this paper, we present the results of a study we performed on 898 workflows from myExperiment. Our contribution is four fold: (i) we discuss the critical problem of identifying workflows and workflow elements, (ii) we provide detailed analysis about the frequencies of re-used elements across workflows, (iii) we consider, for the first time, the problem of cross-author reuse and (iv) we highlight characteristics shared between reused elements.