In many engineering fields, a great deal of development is based on information processing, in particular the storing, retrieving, interpretation, and re-use of existing data. To be more competitive, the fast developing Product Lifecycle Management (PLM) systems are widely deployed by large scale enterprises. In order to improve the efficiency of data management and communication, annotation technology is considered as a promising approach to aid collaboration between design teams in concurrent design and to aid various needs during the entire product lifecycle. In this paper, a classification of approaches to annotation based on an investigation of the state-of-the-art is presented. Cases are used to illustrate how these approaches aid different phases of the product life cycle. Finally, future challenges in the use of annotation in engineering are discussed. Through this research, the contribution of the use of annotation is demonstrated, and further research work is proposed based on the findings.
