All valid points, but I'll jump right to where the money is:
Franz Caching parsed posts is a necessity imo, and that's really what this is all about. Consider storage in the database an implementation detail. We can easily make it so alternative caching mechanisms can be used — perhaps you're right that I shouldn't have implemented this as a field in the posts table, but using Laravel's caching abstraction (disadvantage is that you're going to end up with an n+1 problem if using the db driver). But if you look in Models\CommentPost, you can see that it behaves just like a cache, lazily rendering whenever the cache is empty. 🙂
Client-side parsing is not an option, because third-party apps need to be able to use cooked post data. It wouldn't be right for them to have to implement their own version of every different formatting extension.
As for the UI, I was thinking of using a nice pseudo-WYSIWYG editor like this: http://lab.lepture.com/editor/ Definitely don't want to go full WYSIWYG here, but I think the syntax highlighting is a nice touch. What do you think?
