According to the Ethereum documentation, smart contracts are account holding objects on the ethereum blockchain. They contain code functions and can interact with other contracts, make decisions, store data, and send ether to others. Contracts are defined by their creators, but their execution, and by extension the services they offer, is provided by the ethereum network itself. They will exist and be executable as long as the whole network exists, and will only disappear if they were programmed to self destruct.
EthPolls Smart Contracts:
Ethpolls is open source under the GNU General Public License v3.0. Find us on Github and start contributing to EthPolls today!