Just a quick note: I recently cleaned out my Blogger "spam" folder and discovered that some of my long-time, established commenters had comments held by the folder for no apparent reason. In addition, some perfectly legitimate comments by new or infrequent commenters got stuck, too.
I haven't any control over what gets put in the "spam" folder, and though I try to check it periodically there are times when I don't get to it as often as I should. So, if you've had a comment go missing--please feel free to email me at my contact info in the sidebar. If your comment is not lost in cyberspace but merely stuck in "spam," I'll free it up ASAP.
On a related note--though Blogger does a pretty good job of removing obvious spam, every now and then I'll see a comment that's just an excuse to stick a link to a third-party site. I always delete those as soon as I find them. I have no trouble with regular readers or commenters offering a link to something relevant to a discussion, but I do have a problem with people using something extremely tangential to direct readers to their own business websites.