In this video I give an introduction to smart contracts in ethereum.
First I explain what accounts are in a simpler currency only blockchain.
Then I show how ethereum introduces a second type of account: a code controlled account (aka smart contract).
This type of account does not have a private key but instead is controlled by code.
It can store ether, just like user accounts, or it can keep a balance of 0 and be used to deliver some other function within the context of an application.
I then give examples of how you can use smart contracts.
If you want to tip this video here is an ethereum address for this video: 0xd6d1f455814211e3a79a03faa7bc18c74ca9163c