The 'Molecule of the Month' Website-An Extraordinary Chemistry Educational Resource Online for over 20 Years.

The Molecule of the Month website (http://www.chm.bris.ac.uk/motm/motm.htm) is an educational resource that is celebrating its 20th anniversary. Here we reflect on its pioneering role in promoting new technology for visualizing and presenting chemical information on the web, as well as its achievements, as a free educational resource, both as a teaching aid and as a multi-user, multi-author learning platform. We discuss the legal aspects of such sites, as well as issues around how to make the content permanent. Finally, we look forward to how such sites may evolve in the future.