Abstract
Semantic web services (SWS) have recently attracted much attention because of their potential to automate all common service tasks such as discovery, composition, invocation and execution. The successful implementation of SWS is profoundly based on the availability of appropriate methods for SWS description. There is, however, no consensus in the SWS arena on the significant service elements that make SWS description comprehensive. Furthermore, semantic annotation of those elements is still a manual process where human involvement is a must. Therefore, automating the annotation process is highly desired as the manual annotation is a difficult, costly and time-consuming process. Few approaches exist aiming to semi-automate the annotation task. These approaches have limitations preventing their wide adoption by the research and practice communities. This paper contributes by analysing and comparing those existing semi-automatic Web service annotation approaches in order to highlight the major challenges and provide fruitful guidelines to aid future research. Particularly, a synthesis of service elements that require semantic annotation is provided and then used to assess the completeness of semi-automated approaches. The comparison leads to significant implications for theory and practice.