If Bitcoin is a conservative digital cash system, Ethereum is a platform for building on top of a decentralized ledger. That difference — and its risks — is what this page is about.
What is a smart contract?
A smart contract is code that runs on Ethereum's network and enforces an agreement automatically when its conditions are met. The classic example: a contract that holds funds and releases them to a seller only after a buyer confirms delivery — with no intermediary holding the money, and no trust required in either party.
Three properties matter for a beginner:
- Deterministic. Every node runs the same code and gets the same result, so no one can secretly change the rules mid-transaction.
- Permanent. Once deployed, a contract's code cannot be changed by its author (unless the author built in an upgrade path — which is itself a risk). Bugs are not fixable after the fact; they can be exploited.
- Costly to run. Every operation consumes "gas," paid in Ether. This pricing is what keeps the network usable and is one of the fee types you'll meet when understanding crypto fees.
Smart contracts power most of what you'll hear about in "DeFi" (decentralized finance): lending, trading, and tokenized assets that run on code instead of institutions. These are real, active, and — especially for a beginner — substantially riskier than simply holding a major cryptocurrency. Code can have bugs, and the applications built on it can fail in ways a bank's failure doesn't.
Proof of stake: how Ethereum is secured now
Before 2022, Ethereum — like Bitcoin — used proof of work: miners burned energy competing to add blocks. In September 2022, Ethereum transitioned to proof of stake (an upgrade known as "The Merge"). The mechanics, in plain terms:
- Instead of competing with computing power, participants (stakers) lock up Ether as a financial stake.
- Stakers are selected to propose and validate blocks; they earn rewards for honest work.
- Stakers who act dishonestly have part of their stake destroyed ("slashed") as a penalty.
The shift replaced an energy cost with a financial one: security now comes from the economic risk stakers take. For you as a user, the practical differences are that Ethereum's network fees and transaction behavior changed, and that staking — earning a yield on locked Ether — is a network activity with its own risks (lock-up periods, slashing, protocol changes) rather than a guaranteed return.
Ether (ETH): the asset
Ether is the asset that pays for computation on Ethereum. Its uses: paying transaction fees, staking to help secure the network, and serving as the base asset for the tokens and applications built on the platform. Like all cryptocurrencies, its price is volatile, and like all of them, it can lose significant value. Nothing about Ethereum's design guarantees its price or the success of any application built on it.
How Ethereum differs from Bitcoin — and why it matters
| Dimension | Bitcoin | Ethereum |
|---|---|---|
| Primary purpose | Digital cash — moving value simply and finally | Programmable ledger — running applications via smart contracts |
| Security model | Proof of work (mining) | Proof of stake (staking, since 2022) |
| Supply | Fixed cap: 21 million coins | No hard cap; issuance and fee mechanics are policy decisions of the network |
| Change process | Slow, conservative upgrades | Faster upgrade cadence — more capability, more change risk |
| Beginner risk profile | Price volatility, custody, scams | All of the above, plus smart-contract and platform-change risk for anything built on it |
The honest summary: holding Ethereum is a simpler proposition than using DeFi applications on it. The platform's power is also the source of its additional risk surface, and "built on Ethereum" is not a safety claim.
Frequently asked questions
Is Ethereum a cryptocurrency or a blockchain?
Both, at different levels. Ethereum is the blockchain (the network and its rules); Ether (ETH) is the cryptocurrency that runs on it. When people say "I bought Ethereum," they mean they bought Ether.
Can I mine Ethereum?
No — not since the 2022 transition to proof of stake. Mining Ethereum with consumer hardware is no longer a thing, and any site pitching "Ethereum mining" income to you is a scam. (We cover scam patterns in avoiding crypto scams.)
What are tokens, and how are they different from Ether?
Tokens are assets created by smart contracts on Ethereum rather than built into the protocol itself. They range from stablecoins (designed to track the US dollar) to project tokens to non-fungible tokens (NFTs). Tokens inherit Ethereum's security for their ledger entries, but they carry the additional risk of whatever contract created them — a buggy or malicious token contract can make a token worthless or unspendable.
Is staking a safe way to earn on Ether?
Treat it as an activity with real risk, not a savings account. Staking involves lock-up periods, the possibility of losing some stake to slashing if you (or your staking provider) misbehave, and dependence on protocol rules that can change. It is a network-security activity with a financial reward — the reward compensates for the risk, it doesn't guarantee a return.
Where to go next
From here: how the blockchain mechanics work, the risk picture, and when you're ready, choosing where to buy.