Github and Gitlabs are high quality places to share your code, often projects wish to become open source and use these platforms to engage with the developer community, often code is added then shared again, and in such a way crowsourced code develops.
I am not very active or much of a coder but I have made some contributions to projects over the years.
These all need a lot more work and development.
Anyone can browse and download public repositories but only registered users can contribute content to repositories. With a registered user account, users are able to have discussions, manage repositories, submit contributions to others' repositories.
On January 16, 2013, GitHub passed the 3 million users mark and was then hosting more than 5 million repositories