ExchangeCoin is a cryptocurrency which value is based on real market value of excc.co project, which goal is to create decentralized crypto exchange platform. Their currently available projects are ExchangeCoin and Xchange.me.
A stake pool is used to delegate your voting powers to a third party (the pool). The pool, by it's design, cannot steal your funds. You can read more about it here.
Participating in a stake pool is perfect for people who wish to take part in EXCCoin's proof of stake voting, but:
The source code of this pool is available at GitHub.