DeFi, NFTs & Layer-2s
7 key takeaways
- DeFi is finance run by smart contracts: lending (Aave), swapping (Uniswap), stablecoins (Sky), staking (Lido).
- Yields come from borrowers, traders and protocol rewards — if you can't name the source, it's a red flag.
- Stablecoins (USDC, USDT, DAI/USDS) are the on-chain dollar.
- NFTs are unique tokens: ownership records for art, tickets, domains and game items.
- Layer-2s cut fees from dollars to cents; start on Base or Arbitrum.
- Bridging and token approvals are the two riskiest actions — do them carefully.
- Smart-contract risk never hits zero: diversify and size positions.
What DeFi replaces
A bank matches savers with borrowers, sets rates and takes a spread. Aave does the same with a smart contract: deposits earn, borrowers post collateral, rates adjust algorithmically, and liquidation is automatic. Uniswap replaces the exchange's order book with liquidity pools. Nobody can freeze you, and nobody will refund you either.
Where yield comes from
Lending interest (paid by borrowers), trading fees (paid by swappers to liquidity providers), staking rewards (paid by the protocol for securing it), and token incentives (paid by projects to attract users — temporary). Sustainable yields on major protocols are 2–10%. Anything advertising 50%+ is either incentives that will end or a scheme.
Stablecoins
USDC and USDT are backed by cash and treasuries held by companies; DAI/USDS is backed by on-chain collateral. They let you park value, earn yield and pay globally without volatility. Most DeFi positions start by converting to a stablecoin.
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NFTs without the hype
A non-fungible token is a ledger entry that says this address owns item #1234 of collection X. The art market was the first use; tickets, domain names (.eth), game assets, music rights and real-world deeds are the lasting ones. Value depends entirely on what the issuer attaches to it.
Your first DeFi session
Withdraw $50 USDC from an exchange to Base. Install Rabby, connect to Aave, deposit USDC, watch it earn. Then swap $10 to ETH on Uniswap. Revoke the approvals afterwards at revoke.cash. Total fees: under a dollar. You now understand more than 95% of people talking about crypto.
Watch
Blockchain expert explains one concept in 5 levels of difficulty — WIRED
Frequently asked questions
Is DeFi legal?
Using open protocols is legal in most places; some front-ends geo-block US users on certain features. Taxes apply to swaps and rewards.
What is impermanent loss?
When you provide liquidity to a pool and prices diverge, you can end up with less value than simply holding. Fees may or may not cover it.
What's a bridge?
A tool that moves assets between chains. Bridges have been the biggest hack targets — use official or audited ones and move only what you need.