This list should really begin with: “Satire and polemic writing are only effective when your audience knows that you're sarcastic or angry.” For those who get it, here's the list.
Shameless self-promotion : Prove your worth through your writing and choice of topics. Most blogs are free, so it's not such an exclusive club. And sorry to burst your inflated ego, you're probably not the first person to have thought/written/found/analyzed your post's subject matter.
Comments from the peanut gallery : “Ur so dum i toataly dissagree.”
Pseudo-secrets : If you write about a secret that you are keeping from someone else, don't later complain (on your blog) about being found out. Remember, you can't hide the internet under your mattress or in a shoe box in your closet.
Writing that just takes up space with no motive or message.
Feeling dumber than when I started reading : What was the point of that post? Why did I read your blog when I could have spent time on something far superior, established and respected...like the New York Times or Facebook?
Bright colors and hard to read text : If you're not a designer, stick with a suggested color scheme and font size.
The word “blogosphere” : It doesn't sound cool, tech-savvy, or remotely appetizing. If the blog universe is going to keep up with the times, it needs a snazzier nickname. Sort of like what “web 2.0” did for “the web.”
Less is more : Subtlety is key. If my index finger tires from scrolling, you need a good editor or a ball-gag for your keyboard.
Top-10 lists : For that matter, Top-Any-Number lists. Making a list is a lazy excuse for poor writing skills. Remember essay writing? Intro-body-conclusion? Furthermore, there are inevitably fillers on the list, some of them irrelevant. See number 4 for example.
Poor grammar, spelling and syntax : Ever heard of proofreading? If English isn't your first language, don't write in it!