To be honest, I never heard of them and I just looked through the site for the first time.
First glance, while it is well put together and I get a sense of good intent there I just can't donate 2000+ hours of my time into a pool that codes stuff for a non-profit so that they can donate those works to another NP all so I can get a certificate which I don't think really count's toward anything in my own situation.
To get a better feeling, I walked through the first 15 minutes. Every step was well documented. There were images, videos, and text to walk through each step. The chat room was very busy, which may be typical of a weekend. New people were introducing themselves during the 15 minutes. The local Facebook group stated 99 people, yet activity looks to have stopped in mid-2016.
Nothing in this world is free - this I have always been taught. Secondly getting to know your coding is really about experiencing first hand and maybe do some reading / testing on w3schools and studying lots and lots of tutorials.