Ethereum is a programmable cryptocurrency with many other coins built on top of it. These coins are called tokens and were created in the Ethereum platform without an ICO (which is a good thing because they didn't create more than they wanted to).
They're like apps that run right on the Ethereum blockchain instead of your phone's OS (or Google Play or Apple App Store). Some people even think that these tokens, since they're hosted on the Ethereum blockchain, somehow make it better than if it was its standalone coin like Ripple.
The tokens that other coins like Golem and Augur create run on the Ethereum blockchain. But you have to keep in mind that these coins are different from what we know as Ether or ETH, which is the actual cryptocurrency of the Ethereum platform.
If you send ETH to a token contract address, your money will be lost forever since their contracts aren't made for ETH but for their censorship-resistant tokens, which somehow have value because people believe they do.
And suppose you send a tokens (an ERC20 compatible token) to a wallet address created by a coin like Bitcoin instead of an address created by a wallet specifically designed for its native token. In that case, your money will also be lost since those wallets don't recognize those non-native tokens.