What is art?

To the question
What is Art?
I might answer

Art is the product(s) of human creativity.
Art is what is made by an artist, form combined with content, originating with compelling intent.

and then
How does the world get shaped by what artists do?
In a capitalist world the shape is very different from a world outside capitalism. Like the cave dwellers and pyramid builders, the hunters and gatherers created a different shape world than the Young British Artists with their Saatchi money. They create a different shape, but the world is none the less shaped by those artists and all others. Art is a way of communicating the experience of the artist, seen by the viewer who judges if they can relate or if they cannot relate. That makes the viewer something of a critic. The critic is changed and makes a statement resulting from the art they have seen. Their statement is the product of human creativity making it art. Then it is passed on, and on and on, a web ad infinitum. People make comments to express themselves. It's all communication.