The unabated growth of the World Wide Web in the last decade and the increasing size of the websites have resulted in significant amount of research activity to improve the link structure of the websites. A website can be considered as a directed graph with webpages as nodes and hyperlinks as edges referred to as the Webgraph. The researchers have applied various heuristic, metaheuristic and mathematical programming models to optimize the website link structure. Website structure optimization or reorganization is also considered as a graph optimization problem. This paper presents a pioneering comprehensive survey of the recent and the most successful models that are based on transformation and are developed for the newly emerged website structure optimization (WSO) problem. Transformation based models alter the link structure according to the browsing behavior of the users to ease the navigation for all the users. In this article, the models have been classified and discussed. The origins, formulation and comparison of models have also been presented.