Can you explain the business model behind the payouts you make as part of app mining, please? (https://app.co/mining)

In simple terms; I'm trying to get my head around what Blockstack gets in return for paying developers to use Blockstack Auth ?

Also, you may want to investigate the rounding of Dmail's figures shown on that URL ^^

At the time of writing the page shows a lifetime payout to Dmail of $19,999 yet last month it shows they earned $20,000. Surely "lifetime" earnings must always be >= last month's figure, as last month is part of "lifetime" ?

Thanks