If you are a traditional artist and a little nerdy or just curious about your paints, then I have something for you: sunandcolors.com
It's a library of watercolour swatches with pigment information, properties and the results of a lightfastness test. It's still growing and what really excites me: it's turning into a community project.
Latest update: we've added the full range of Mijello Mission Gold to the database.
Enjoy!