It says on their white paper that they don't have to complete any product. They'll tell you it's a "loophole" by their lawyer but it's all bullshit. It's so when they get sued, they can show that little line in the white paper that puts them in no obligation to complete a project.
I'm 100% sure we are not alone, will we be visited or come in contact with this other civilization? Probably not in the nearest future. I wonder how far their development reached, how do they communicate and intract with eachother?
It is really hard to trust any site with private keys. I think its best to use just another temporary wallet for etherdelta, its going to be safe. You can than send your money to another wallet.
American ICOs are regulated and you have to pay a fee to register and even then you might not get approved.
So much easier for these people to make it outside the USA and have USA investors use a proxy or have someone buy it for them.
It really doesn't change much if US investors aren't allowed. Most companies meet their goals and American investors who want the tokens bad enough will find a way.