The Ecoin Airdrop was something I stumbled on about 6 months ago and I will be honest and tell you that it annoyed the hell out of me that I couldn't access any of my coins for ages!
But let's be honest, considering this is a completely free project and they are not selling their coins in any ICO or anything like that letting everyone simply sign-up access their coin and proceed to sell them on ProBit straight away the value would tank and the project would die before it had a chance to start.
The basic principle is you get coins for signing up, then more coins for referring people to join the Airdrop. Once you have met the criteria of X amount of referrals you can withdraw X amount of coins per week. In theory the more people that join and own the coin the more the value increases.
At this stage I am actually feeling really positive about Ecoin. I am earning 11% interest on the coins I keep in my savings and I can withdraw 2000 coins every 30 days. There appears to be reasonable attention given to the project and always ways for anyone to earn more coins and even now the option to trade referrals so if you can't get your own referrals you can buy them or vice versa.
It isn't much at the moment but for something that has cost me absolutely no money upfront it is giving me a consistent passive income that will hopefully further increase in value. From this perspective I would have to give it a thumbs up and put it out there for your consideration.