The increasing complexity of the web is reflected by the enormous quantitative growth of web resources. Those resources are also growing in terms of complexity, since they are no longer limited to data items and include a wide range of functionalities and services. This evolving scenario has produced a novel technological paradigm (known as cloud computing) able to accommodate complex requirements (such as scalability) in the current socioeconomic climate.

This paper addresses the service discovery problem that is going to arise once the number of resources increases inside cloud platforms. The solution provided by the authors uses semantic technologies to enhance the retrieval process through the automatic integration of common descriptors (in natural language) with semantically rich annotations. The annotation model adopted in the work supports multiple document formats (Extensible Markup Language (XML), Hypertext Markup Language (HTML) and portable document format (PDF)), a multi-ontology environment to cope with several domains, and document and ontology evolution. According to the authors, an evaluation of the tool has shown very promising results.

The paper is well written and well structured. It provides a solid contribution for a wide audience, including nonexperts in the field. The solution looks well suited in the context of the current semantic technology, as the extensive (and much appreciated) analysis demonstrates.