blog culture question: random comments of agreement (on other blogs)?

[BZB]

I tried to Google this but I'm not sure how to write the query, so I thought I'd give this forum a shot. Often in other blogs that don't have active moderators someone will post a comment that goes something like this:

"I agree that is a very well written and thoughtful post and made me think very much about the topic. I have learned much about this topic and hope you will post more on this topic. It is very insigtful and brillant."

Usually there are typos and grammatical errors. I used to think these were spam, malware, or phishing but there is no link to click on. Why would someone go to the effort to post these odd, generic comments? Have any of you seen this before and have any insight?

[Mrs. PoP]

Most likely SPAM. Even if that comment doesn't have a link, many blogs have comments set up so the first comment by a reader is moderated, but once they are approved future comments don't get moderated.  This gets them in the door to leave other comments with spammy links.  At least that's my theory from seeing them make their attempts at posting on our blog. 

[basd]

Most likely SPAM. Even if that comment doesn't have a link, many blogs have comments set up so the first comment by a reader is moderated, but once they are approved future comments don't get moderated.  This gets them in the door to leave other comments with spammy links.  At least that's my theory from seeing them make their attempts at posting on our blog.

This.

As an author of a Wordpress.org-based blog, I get hundreds to thousands of these every week. Luckily Wordpress / Akismet does a great job of filtering them out. It's the main reason I want to approve at least one comment from someone before they're allowed to post comment on my blog.

[BZB]

Ah - that makes sense. Thank you for your insigtful and brillant replies :)