So, if one begins with the basics, the first principles, so to say, the purpose of all these ad/ bounty campaigns is to discover and reach prospects and convert them into customers/ subscribers. Since everyone distrusts everyone else on the Internet, (and with good reason), bounty campaigns are the seed 'bait' to prove a site's bona fides.
But, this schematic only considers a distrusting set of prospects viewing a distrustable, unknown entity offering them product or service. The other side of this equation is a distrustable/ disreputable horde of superficially appearing prospects who are immune to conversion, and whose only object is to game your system for airdrops and the like freebies. This is the scenario on Twitter. I don't know much about the Facebook angle, but maybe that too has a similar problem.
Hence, the rush for crypto/ blockchain conferences, so that genuine, new prospects can be discovered; and the advertiser can put their best show in front of them. Unfortunately, that angle too has dried out now, it's more like every seller pitching to every other seller at these conferences!
The solution is present but tedious to implement. Also, your project needs to be really sound and convincing for this to work. This solution involves directly contacting individuals, whether via Twitter, or their email, or even using direct mail. So, first you need to identify the genuine people who could be prospects, and then reach them, even using direct mail where necessary.
My $0.02!
Exactly my thought about Blockchain conferences - although they seem a great choice (but quite expensive - especialy if you want to have our own booth) they are becoming a place where everyone wants to sell something but no one is interested in buying.
