If I have something to say that will take 140 characters or less, then I will use Twitter to say it. If I have something to say to a particular person (or persons) on Twitter, then I will use Twitter to say it to them. This second rule also applies to Friendfeed, Facebook or anything else I happen to be on.
However, if I have something to say and it doesn’t fall into any of the parameters of the first paragraph, then I will use my blog to say it. Twitter is a microblogging service and for a lot of people (including me), it has taken the place of actual blogging. I plan on changing my online behavior to the added benefit of my sites. I know I am not the first person to have this epiphany but we all get to where we end up at our own pace.
Not all of my new blog posts will be treatises or manifestos, some times they will just be what I am thinking about. Since this is what I am doing on Twitter as it is, I might as well expand my explanations and make them a little more understandable to others.