The Sloan Digital Sky Survey (SDSS) is the largest ongoing sky survey. It regularly makes data releases to the astronomical community. From a macroscopic point of view, a profound question is: what is the role of SDSS data releases in the evolution of the relevant scientific fields? In this paper, we introduce an integrated approach by combining statistical, information-theoretical, and symbolic methods for text data analysis and show how this combined approach can distinguish thematic variations associated with the different data releases.