Question: Anyone using colorjack? Someone here on SO mentioned it the other day, so I checked it out. It is a really slick tool, but I am having a hard time figuring out how it is used? 

<http://www.colorjack.com/sphere/>

I do all web development using asp.net, and my strength is in back-end programming but I'd love to beef up my design skills, and it seems like colorjack might be helpful, but I am not grasping how it should be best used...there is very little guidance on the website.

Do you use it? At what stage? How does it fit in to your web design toolbox?

edit: if not colorjack, but you use another similar tool, same question applies - where does it fit in?

Answer: 
Colorjack is a color scheme generator. 

Is useful if you want to find quickly a nice color scheme for your user interface. It is based on color theory: schemes can be analogous, complementary, triadic, tetradic and so on...

It also has the useful function to simulate how the generated color schemes are seen by people with some view limitation (protanopia, tritanopia and so on...).

It gives you the possibility to export your color scheme in a format compatible with illustrator, photoshop and other programs for graphic designers.
Tools like colorjack are used to help you pick a color scheme for your design. There are many methods people have devised to pick a group of colors that will look good together, based on different aspects of [color theory](http://en.wikipedia.org/wiki/Color_theory). I found this short [article](http://www.colorjack.com/articles/color_formulas.html) on the Colorjack blog that describes some of the ways you could pick a color scheme and the relative merits of each.

You usually use the color scheme generated by a tool like this as a starting point, but you may end up customizing or tweaking it to your specific needs.