Blog???

What exactly is the point of having a blog? Is it to write down things that interest you, the political world, issues that surround the world, or...about whatever you want? This has been bugging me so much. I keep thinking I'm writing stuff that shouldn't go on a blog. I bet some of the people who read my blog are probably thinking "Who in the world is this Alishah person? She's weird."
So, if any of you know what should go on a blog...please let me know.