Your website actually has a decent design. It's easy to read with big enough font size, line-height and padding and basically it has no glaring annoyances that plague badly designed websites.

I say even more minimalism could do well in regard to the color scheme, and probably the flow of reading on the home page could be improved as well (e.g "Start Using Tarsnap now!" could be placed right underneath "Tarsnap pricing").

Other than that, buttons linking to quick download and registration should do well, too.