Marc Andreessen's Eleven lessons

Marc's disabled comments on his (excellent) blog. Marc, I see at least two issues with that: First, a lot of times I only have a sentence or two to add to a post and it hardly seems worthwhile to create a brand new article on my own blog. Second, if anything it's even easier to spam trackbacks than it is comments! Although I don't have enough readers to bother about any spam-blocking besides the Blogger default captcha, surely you could come up with some mechanism to ensure a human is the one entering the comment. And isn't it a shame to restrict comments only to those who have their own websites?