There are not many free slots in the campaigns. Probably many people think that $20 is still 20x more than $0
Plus, to be realistic, the power of the Bitcointalk forum is declining, and so is the payment rate for campaigns. Although $20 for Jr. member ranks as quite the correct payment.
I agree that the Bitcointalks traffic has been on a decline over past months but in the late 2018 to 2019 period just during the previous bull market's hangover, most of the services pulled out from campaigning and except for some very few signature campaigns like that of chipmixer, fortunejack, bustadice. Most campaigns had legendary ranks, getting around $50-$40 and would last only for a couple of weeks. Member ranks would have to part with something close to $10
For example, just a few months ago, $50 a week on altcoinstalks was considered miserable.
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How is it so far over there? Are there new services streaming in to advertise, or the whole thing just ended at the migration of mixers?