Since the completion of the yeast genome sequence in 1996, three genomic databases, the Saccharomyces Genome Database, the Yeast Proteome Database, and MIPS (produced by the Munich Information Center for Protein Sequences), have organized published knowledge of yeast genes and proteins onto the framework of the genome. Now, post-genomic technologies are producing large-scale datasets of many types, and these pose new challenges for knowledge integration. This review first examines the structure and content of the three genomic databases, and then draws from them and other resources to examine the ways knowledge from the literature, genome, and post-genomic experiments is stored, integrated, and disseminated. To better understand the impact of post-genomic technologies, 20 collections of post-genomic data were analyzed relative to a set of 243 previously uncharacterized genes. The results indicate that post-genomic technologies are providing rich new information for nearly all yeast genes, but data from these experiments is scattered across many Web sites and the results from these experiments are poorly integrated with other forms of yeast knowledge. Goals for the next generation of databases are set forth which could lead to better access to yeast knowledge for yeast researchers and the entire scientific community.