Side topic in a blog post

This question has probably already been asked but I am having trouble describing what I want - one of those "I know it when I see it" kind of things. I want to be able to put s short bit of text "to the side" in my blog. Its like it is not directly on the blog topic, but its related. That is, I can see how my topic might trigger a question that my little side bar answers. Vague enough? I think there must be a name for it in blogging/writing parlance. I have seen them on other blog site like an outlined inset with different color background, etc.