From Scientific American, research has shown a link between writing (and by extension blogging) and improved memory, better sleep, bettero immune cell activity and even faster healing after surgery (damn, I should have been writing instead of reading so much) [via Yogamum ]
Flaherty, who studies conditions such as hypergraphia (an uncontrollable urge to write) and writer’s block, also looks to disease models to explain the drive behind this mode of communication. For example, people with mania often talk too much. “We believe something in the brain’s limbic system is boosting their desire to communicate,” Flaherty explains. Located mainly in the midbrain, the limbic system controls our drives, whether they are related to food, sex, appetite, or problem solving. “You know that drives are involved [in blogging] because a lot of people do it compulsively,” Flaherty notes. Also, blogging might trigger dopamine release, similar to stimulants like music, running and looking at art.