Jorge, what do you think of the idea to put a "note" option to Dock and Shelf items?
Just an extra field where you can put in a few lines of text, that is shown below the name on mouse over.
You could put in some help/basic info for apps that you don't use very often.
Like the most important hotkeys, or a short description of a special function, etc.
I think this would be quite useful.

Edit: Maybe only for Shelf items, since the popup shows generally more info.
I think it would look too clunky on Dock labels.
The Shelf is also more likely the place, where you put apps that you don't use very often...