If you want to fine tune your colors, or simply edit the colors completely arbitrary, you can change to "Direct Edit" mode. In this mode you can click each of the 6 color swatches to edit each color individually.
If you have just the slightest experience with graphic applications like Adobe Photoshop or the like, everything should be dead easy to use.
When editing a color, you may choose to edit it by using RGB (Red/Green/Blue) or HSV (Hue/Saturation/Value) sliders. The former tends to be the more "digital" approach, while the latter is very useful if you are familar with the "color circle" terminology. Try it out, and see what you like the best!
Clicking the "Photoshop Color Table (.ACT)" button will let you download the blend as a small file that can be imported into Adobe Photoshop (see the FAQ for more info).
"Send blend by email" will give you a single URL to open your current blend directly. This let you "bookmark" the blend in your web browser or even send the blend via email. In this way, the recipient can view your blend, and eventually fine tune it, export it, etc.
Yes, you can set up multiple machines to access the same set of saved blends. Simply follow the guidelines at the Cookie Copier page.
The algorithm is based solely on my personal preferences.
By clicking this button, the tool will calculate the PANTONE® spot color number that has the RGB-simulation closest to the current color. Please be aware, that this is no more than a rough estimate (even though it seems to get very close most of the times).
In Adobe Photoshop, open the Swatches palette. In the upper right corner menu of the palette, choose either "Replace Swatches..." or "Load Swatches...". From the file dialog, be sure to select the "Color Table (*.ACT)" file type, then locate the *.ACT file you just saved. Click "Load". The colors of the blend will now be loaded into the Swatches palette, ready for use in Photoshop!
Quite a few programs can load colors (aka "Swatches") from EPS files (e.g. Adobe Illustrator and Adobe InDesign). For example, in Adobe Illustrator CS, go to Window > Swatch Libraries > Other Library ... and pick the EPS file you saved from this site.