Faculty of 1000 review of Heidelberg et al 2009 article:

These authors present a fascinating story on the warfare between viruses and bacteria within a microbial mat community.
Comparative analysis of the highly variable CRISPR spacer or ‘viritope’ sequences present in the genomes of two cyanobacteria isolated from a hot spring microbial mat community and in the metagenome of the viruses within the mat provided insight into the population dynamics and the co-evolution of the cyanobacteria and their viruses. These findings might further our understanding on the role of viruses in shaping microbial diversity, which is a highly unexplored topic.