I deleted all the comments off my blog, threads and posts because they were not related to any of the topics. Comments were made on immigration were about weight loss, male enhancement and such. Comments on my music blog had nothing to do with music, answering the post or anything remotely close to it.
Comments that are general in nature like "I really like what you wrote" will be deleted since they don't apply to any specific topic but were used just to get pings and trackbacks posted.
If you want to post a comment and have it approved then it should have something to do with the blog, thread, post or the site and it should make sense and I will not approve any post that promotes anything sexual unless it is a post to help stop circumcision of women or some valid movement. I will not approve any comments that are only trying to promote that persons website unless it relates so the topic. I will however approve comments that relate to the topic and are deemed relevant to me but if it appears to be spam it will be marked as such and deleted.
I delete over 15,000 comments and if your comment got deleted and was a valid comment then I apologize and ask that you resubmit again with appropriate comments that are on topic. Comments that just praise my writing style or knock my abilities will also be deleted since they do not apply to the topic.