I would recommend using a tag as a trigger. Therefore, students add say ‘microblog’ or ‘mb’ as a tag and it would get pushed through. Then you can decide if you include a title or not to decide short or long post.
In the case of a titleless post, I have taken to using the slug to explain the post.
I am really interested in the possibilities of using Micro.blog with something like Edublogs.
Want an 8 cylinder car, but don’t want to pay for the increase in petrol
Want cloud computing, but don’t want to invest in quality Internet
Want a holiday, but don’t want to pay for accommodation