I use WordPress for http://pokercopilot.com/blog. I've turned off comments for the site, because these days, most comments you get on popular blogging platforms are spam. When the comments on our site are not spam, they tend to be support requests. Blog post comments do not make a good medium for conducting customer support.
And yet...the comments still come. I've turned on "comments need moderation", so they get quarantined, and I have to mark them as spam or trash, or let them be published. But they still come.
I was surprised that turning off comments only turns off the UI for making comments. If someone knows how the WordPress API works, they can programmatically add comments to your blog. WordPress's support says that this can't be disabled, and instead you should purchase a subscription to the Akismet anti-spam service.