Just a way to create a checklist for blogging and make it visible to all your authors on the Edit Post page.
There's a new "Blogging Checklist" menu under the Settings tab. Go there and enter what you want.
Just use a pair of brackets, and they will become checkboxes
Sure, go nuts. Okay, actually be careful. If you leave tags unclosed, you might make the administration pages behave weirdly.
Yes, this plugin does allow you to inject HTML into the Admin pages. However, only an WordPress Administrator can change the checklist, so it's not really a big deal.
That's not the point of the plugin. The checklist is just a reference card. The checkboxes are form elements, but these just allow the post author or editor to note which tasks he or she has already completed.