I find this particularly useful for my own designs, as I care quite a bit about design principals, and want to try to build applications with simple yet beautiful UIs, but I tend to fall flat on Color.
Part of the problem may be that I have a color deficiency- Greens and Greys blur together in particular, but more so, I tend to identify color primarily by intensity, then by hue, which means that I get them mixed up on occasion.
Something like this allows me, and other design challenged individuals to experiment, and look at sets of colors that often go well together.
While there isn't a Save feature for the website itself, it does allow you to download a color set to use with prominent applications, or to create a bookmark to upload..
I also love that this is available as a Widget, so you can run it locally in Dashboard.
You can save the URL of the color scheme by clicking the "sphere" link on the right hand side of the webpage. Is this the save feature you were looking for? Or something else?
I find it pretty useless-- color is a 3-dimensional space, and this site seems to have left off a dimension (saturation is missing --degree is hue, radius is color).
I find http://www.colorschemer.com/ much more useful, though non-free. In particular they have a cool feature that lets you extract color schemes from photos.
