Ask HN: Does the color scheme in a website affect signups?

After you've asked this kind of question informally, you may be interested in resources like this:

Color Harmony Compendium, A Complete Color Reference for Designers of All Types

http://www.amazon.com/Color-Harmony-Compendium-Reference-Ann...

more common examples would be white blocks on black background vs. light colored blocks on white background.

Does anyone like to have lots of white (ala facebook)?

thanks guys! I was wondering if someone already made an a/b tests purely on color schemes. that would be very interesting.

Yes. Hugely. It needs to be easily legible, and you need a clear call to action color.

I'd suggest looking at successful sites that serve your target market, and looking at what colors they use. I'm guessing you'll find lots of black/blue/grey/white sites, with orange and green calls to action.