Pretty much what title says, i think it would be great to be able to backup your palettes locally.

and in different formats available, just like from colourlovers

How would boon usage would work, since technically you can create your own palette files on your PC and upload them to BoTB.

imagine a "export/download all"-button where u can download all palettes as zip (maybe on your settings-page rather than on the palette editor page). inside the zip are your palettes "BotB Palette [id] - [name].json" (or whatever format is used) and if you wanna import a palette, you still have to buy a new one and click on a "import"-button where u can select one palette.
single-palette-download should be an extra button as well, on every palette page, not only your own

I think it wouid be even cleaner and more compact as a single file, in a structure similar to pythonic list of dictionaries, where each dictionary is a specific palette, and its key-value entries are the colours.

Except with such design, for the single palette import to work, BotB would need to parse the input and ask which one you want to import.