Daily Divs Network, or DDN, is an open source, honest and mathematically verifiable Ethereum smart contract. On a simple level, the contract is responsible for giving out a certain amount of DDN tokens to whoever gives ETH to it. On top of this, it can also give out ETH should you want to sell your DDN back to the contract. Both of these things are done in such a way that if completely liquidated, every single wei (the smallest unit of ETH) can always be accounted for and paid back.
Here's where it gets tricky, for every DDN token that exists, the price increases by a tiny bit and will also decrease when they are eventually sold back to the contract. This is more complex than you probably think but the contract needs to accurately determine the output for this variable price rate. This mechanism is what gives the contract its 'ponzi scheme' nature but in this case, the rules are very clear and most importantly, immutable and decentralized.
The final feature of the contract is taxes. Upon both buys and sells, a percentage is taken off the resulting ETH amount and distributed proportionally to all DDN holders. You can then either withdraw your dividends directly to your wallet or reinvest it back into buying more DDN.