Recently, a question came up asking if requests for platforms to share works on is on-topic on our site. It is not (with the current exception of our Community Gallery).
But in order to help users who are asking after these platforms, they can be referred to this thread, where we can assemble a list of suitable online platforms to share handiwork and artworks.
This is not intended for promotion of those websites or services. However, (critical) personal experiences and recommendations are welcome, and, in addition to the intended audience and medium, an overview of strengths and weaknesses of the platform would indeed be very handy.
For a clean overview, let's try to have one platform per answer, so other users can comment, and useful information easily added to the body of the answer.