I think I'll be nice that...
I Think it would be a good idea that the lessons that don't have any Tips or doesn't teach any rules it can be considered the idea of putting the best comments of that lessons as a Tip. There are some comments very helpful in understanding some words, meaning and grammar. The comment can appear with the name of the person who wrote the comment (if that person wants obviously :) ). And later it can be think to put (like in a ranking (?)) the people who made more contributions to the course via comment. Just saying! :)
PD: sorry my english I'm not very good at writting it.