Is it common? Or do we really have to introduce it? I mean, do we really need to make our first post sounds like an introduction. I believe so. I think it is just courteous to give your readers a heads up on what they might expect from your blog..
You can either make a list of what are the topics you will tackle, make an introduction of yourself or why did you choose that title. Think of it as an introducing yourself to a new acquaintance. Make it simple and short, not scary but amusing. I know my intro is not good, but hey that's why I am telling you this. LOL