You might see modals like this from time to time when you log in and visit the homepage.
It's a little in-app feature education, if you will. It's marketing too, in a sense, as sometimes we're using it to tell you about PRO features. We podcasted about that just recently:
That one above is about the Dashboard. We chose that one recently as we've had some feedback from people telling us it's too hard to find their own work, and it turns out they had never tried the Dashboard, and once they had were very happy with that.
The first time we ever did this style of in-app notification was when we released the Private by Default feature. That was met with much enthusiasm. We worried that these types of notifications might cause pushback (get out of my way! I'm trying to do something else!), but we've heard almost none of that and plenty of thanks for letting us know feedback.
You might see modals like this once in a while going forward letting you know about features of CodePen you might not be aware of.