Blog spam comments are often the result of a user’s blog being listed in search engines as a spam source. This can happen if your blog has been flagged by Google, Yahoo! or Bing as spamming content.
As a result, anyone who visits your blog and sees your spam comments will be likely to think the same thing about your blog.
To make matters worse, many blog spammers use automated programs to post comments on blogs, making it difficult for the site owner to identify and remove the comments. This means that even if you remove the spam comments manually, they may still reappear in a few days or weeks depending on how quickly the spammers can re-post their comments.
In conclusion, if you notice that your blog is getting a lot of spam comments, it may be because Google, Yahoo! or Bing have labeled your blog as a spam source. If this is the case, it’s important to take action and remove the spam comments from your blog before they cause any damage.