Curecoin vs Foldcoin vs Ethereum

Hello,

I'm a nooB to all of this, and I'm still trying to wrap my head around a lot of this stuff, and I'm trying to figure out the differences between the Cryptocurrencies that tie into Fold@Home, namely Curecoin / Foldcoin / Ethereum.

Foldcoin seems to be very similar but for some reason never took off.