the advertisement blog disguised as a regular blog
If your blog is for the purpose of promoting your church, your business, or whatever and you are upfront about that - ABSOLUTELY COOL and also a very effective marketing tool!
For an example of someone who does that effectively check out http://ellementstudios.wordpress.com
But if you are one of these people who uses their "regular" blog to continually promote their books, modeling career, speaking schedule, new business, or whatever..... please be up front about why you are blogging. You have an agenda to promote - it is cool! Just don't be so shady about trying to accomplish that promotion.