I think it's legitimate, but the coins you can use to earn interest are mostly only the ones you can find on yobit, which are all shit coins.  It's like trying to earn interest on the venezuelan bolivar or whatever it is that's hyperinflating down in that country.  They do have investment plans for btc, but I think you'd have to be on the lunatic fringe to deposit a coin that valuable on yobit so as to earn money with it.

I think I'm done with this campaign after the next payout, assuming the wallet doesn't get stuck again.  I've even earned those pennies of bitcoin on cryptotalk, but it's such a lousy forum that I know anything I write is just going to waste because it'll never get read.  That's how bad it is on that forum.