  Herbertsmithite, ZnCu3(OH)6Cl2, is the prototype candidate for a spin liquid
behavior on a geometrically perfect kagome lattice. Its discovery and the
absence of any evidence for spin-freezing down to the lowest probed temperature
to-date enable one to explore the properties of kagome-related physics in an
unprecedented temperature range. We review its properties and discuss some open
issues. A tentative comparison to models is also performed.
