"It seems very pretty," she said, "but it's rather hard to understand."
I am sure whoever commented didn't read the article. I guess popularity comes at a price. The more popular your blog is, more such comments to attract attention.
This is a bad example of it. But this is a billable activity when done right. There are companies that pay marketing firms to have people read context-relevant blogs and put in comments with a link back to their website to attract more traffic.
RTP: I know it's a billable activity, but on my blog so far I haven't come across a single example of it being done right. Here's another one from the archives: the comments on a review of Upamanyu Chatterjee's Weight Loss. (I've actually deleted a lot of the comments - should've kept them!)