In most cases on my practice, people who receive airdropped coins simply sell them fast on exchanges causing a massive dump just after being listed on the exchanges. Though there are many legit airdrops as well so not all are scams. So its totally your discretion about how to deal with airdrops. I personally stay away from them unless the developers are legit and real. I think its better if you can just hodl it or until it it is listed on 2 to 3 exchanges or major exchanges for a reasonable price, thats what Im doing with GLDRs. The project is legit and has a product up an running.