[beeneto]

Comments sections improve blogs because they are a place where readers can point out errors in the parent article.

Sending an email or tweeting the correction is more difficult than making an anonymous comment, and would then need the author to both concede their mistake and take the time to correct the article. Until they do that, everyone who reads the article risks being misinformed.

I can see an argument that comment areas are less necessary on purely opinion blog posts like this one, but on technical blogs they are much more useful, and even on opinion posts I think giving space for dissent is probably a good general rule to follow. For example James Shakespeare seems to base his opinion on the belief that everyone has the same "blog reading algorithm", which I don't think is the case. If there were a comments section I'd post that suggestion, but because of the increased overhead/social investment needed to send an email or tweet I'm not going to bother, and he will probably never read that dissenting opinion.