A historian friend just placed piece of writing on the Huffington Post, discussing tomorrow's elections in South Africa. The immediacy with which she conceived the idea for the article and shopped it to HuffPo (all happening within a matter of days) shows just how seductive web publishing can be. If Laura were to write an academic piece about these elections, it would take months of research and carefully crafting her argument. And the likelihood of the average Joe encountering and/or reading it would be almost nil. Not to mention that it would no longer be timely or pertinent to tomorrow's election.
Sure, there's space for all genres of writing in this big wide world, but it's so thrilling to write with an immediate audience in mind--to know that your piece will gain circulation instantaenously. The process of writing traditional academic work--journal articles or monographs--is incredibly time-consuming and one gets the sense that they will only have a handful of readers.
Which is why I'm a webwriting addict, myself.