Blog comments are valuable to a blog, but they can also be a significant source of spam. Prominent marketers like Neil Patel estimate that as much as 40% of the content in their best blog posts is from their conversations with engaged users in their comments! On the other hand, some prominent bloggers like Seth Godin don't even have comments enabled on their site. He's leaving a lot of content off the table, but then again, Neil Patel's site is quite a bit larger and has higher traffic.