Probably politics. I'm not the most knowledgeable person when it comes to this arena, mostly b/c I'm not too interested in other opinions aside from my own. Just kidding! But, seriously, people are pretty one sided when it comes to their political views and I'm not a fan of alienating people or challenging their beliefs with my blog. My blog is about fun, and family, and friends and those are things that everyone can relate to.
I try not to blog about anything too personal. I stay away from naming the actual places we go. I'm a bit paranoid with these days. Also, I try to stay away from the topics that are too controversial. Don't get me wrong, I like to have good discussions and speak my thoughts at times. After all, thats kind of the purpose of my blogging. But I dont like to discuss things just for the sake of sparking an argument. The hot topics are SAHM vs. working moms, breastfeeding vs bottlefeeding, crying it out, vaccines, religion....etc. I try to be sensitive to all mommies views :)
I would have to say religion, politics and XXX. I do post about some things such as KY and a nighty, but never anything about my personal sex life. If I had marital issues, I wouldn't post about those either. I do just about everything else though.
Agree with Karen, I will not blog about sex. Maybe before I had a kid, but definitely not now... I also just had to turn down advertising from Eden Fantasies b/c I just won't promote things that are not family friendly on http://dearcrissy.com.