Accessibility and usability

Have you ever seen when Google implements new stuff and then you access it for the first time? They use to show you some contextual help in order show where each feature is. You follow the steps and see everything you should see, then you will never will see this help again. It is made to be seen only once. Of course, if you need, you will find regular help on the proper area.

I would like do something like this on my Moodle. I would like to show people which is new, but only once per user per screen.

Any clue?

Thank you, guys.

P.S. usablica works fine, I just want it works only once.