but I was paid by that site for 0.02 eth for a measly less than 20 number of posts
That is $6.
The signature campaign is offering up to more than 40x that amount. Suppose they pay out the lower-ranking participants that they accept right now, and will stop when they accept higher rank members. That means a lot of free traffic and assumed reliability, at least to start with.
This hypothesis also mimics the standard protocol of a ponzi and/or con.