Gary Illyes from Google announced on the Google Webmaster Blog that they disabled the ability to post or view comments on that blog. He said most of the comments ended up being off-topic or even outright spammy. So they decided to drop them completely versus spend the time moderating those comments.
Trust me, I know how spammy comments can get. I probably spend 30 minutes a day just dealing with comment moderation. I don't actual spend the time counting it, but I have a dashboard for managing it and I check it throughout the day. The biggest time suck is when I wake up and have to catch up on all the comments while I sleep. It is a lot of work.
But I deeply feel comments are part of the culture of blogging. If you want to post stuff on a site, without allowing comments, then call it a news site or press release site. Blogging is about community, collaboration, etc. So it upsets me to see comments go away from the Google Webmaster Blog, but I am not surprised Google took this step. The comments were pretty poor.
Google is now directing people who want to comment to go to the help forums or ping them on Twitter.
Forum discussion at Twitter.