When you have a blog of your very own, you can say just about anything that you could possibly want. While some blog hosting programs have issues against such things as sexual perversions like incest or bestiality, and prefer that you limit your hateful speech to things you hate in life (as opposed to your least favorite races or religious faiths), the simple fact of the matter is that you do have an immense amount of creative control over what you put into your blog. Of course, the bad part of this entire thing is that what you put into your blog says an awful lot about you, and who you are as a person.
After all, your blog is your personal thoughts, projected outward for the rest of time, so that the entire world can see them. The people who pay a lot of attention to what they write in their blogs are generally the people who say the most thoughtful things in the first place. For most of us, on the other hand, a blog is usually little more than a place to vent our latest frustrations in that tiny personal melodrama that we all call a life.
You do need to remember, however, that your blog is not nearly as personal as the diary that you would keep under your pillow. If you have some annoying interloper invade your privacy and read your diary, you would most likely be infuriated. But consider that more than a billion people can read your blog. So if there is absolutely anything in there which could theoretically be interpreted as being a bad reflection on who you are, it might be best to just omit it.