I have participated in quite some airdrops in the past and quite frankly never profited from doing so. I just lost track of what coins I have and all the projects I had these free coins of. Ultimately one project I looked at, the cultural coin, changed my mind on that: The guys did purposely opt against an airdrop since they didn't think they needed to give away their coin for free in order to be successful. I think they are totally right: Now I only look for projects without airdrops because they just have a more serious, thought-through look to them. If I can see they have a good project, I participate in the ICO or buy coins. But thats because I like to support the project and not to get free stuff without getting anywhere with it. Total waste of time if you ask me.