A more stringent, ecologically based demarcation of bacterial taxa would benefit many areas of microbiology. Beyond the public-health benefits outlined by Luo et al. [5], identifying the full set of putative ecotypes within a pathogenic taxon could lead to discovery of clades that are perhaps subtly different in their disease-causing properties and their modes of transmission [13]. Also, recognizing taxa at the ecotype level could be useful in vaccine development [18] and in industrial biotechnology [13]. In addition, the broad definition of bacterial species has led to innumerable errors in population genetics, where parameters are estimated assuming that all local members of a species taxon are part of the same population [18]. Finally, perhaps the greatest cost of broad-brush species taxonomy is inflicted upon the field of systematics itself. When a systematist discovers a bacterial group and sees that it can fit into one species taxon, the traditions of systematics provide no motivation to further explore the ecologically distinct clades within the species. The research in systematics is then impoverished by a standard of detail that leaves much of a clade's diversity uncharacterized.