This is a valid question. I'm the author of the blog and I've asked this myself in the past. The main reasons why I haven't done this so far are - artistic freedom (regarding the form/structure, the style/tone, the interactivity), - the process (I prefer not to have long discussions and unexpected revisions; but I must admit that I should collect actual experience in this regard), - and the lack of attribution (part of it is certainly vanity, but I'd also like to make a living out of this at some point).