v; Even though you're typing, it doesn't count you as being inactive. The computer knows you're typing, but Mibba doesn't. You have to be actually doing things on Mibba - browing the journals, the forums, clicking through stories, etc., so Mibba knows you're still online. Sitting on one page - the drafts, chapters, etc. - counts as being inactive, because you aren't doing anything other than sitting on that one page, not moving around the site.
We weren't 'Inactive' though. We were typing the WHOLE time. And right when I went to preview it, it signed me out of my account. So we had to re-type it, and now it's not as good as it could have been. ):
If you're inactive for a certain amount of time, Mibba will log you out. That's why you should always write on a word document and copy and paste in onto Mibba in case something like that happens, then you can always re-paste it.