It's a name registry like DNS that points to Ethereum addresses. Thus, I could send ETH to kleinbl00.eth, rather than a crazy long mix of letters and numbers. The fanciest part, is that the service runs on Ethereum itself. It's decentralized.
Yeah I found a medium article but that doesn't really cover it. So basically this is the framework by which you would in the future be able to use Ethereum like venmo or some shit? So for example, if my name was James Kieth I could register james-ki.eth and people could send me ethereum without some big dumb hash? Is that the basic idea?
The way I understand it, is that ENS tries to mimick DNS but add Ethererum-stuff to it. So instead of your DNS resolving http://www.hubski.com to http://22.214.171.124, the ENS can resolve kleinbl00.eth to your Ethereum wallet address. Or to some other bajingojargon like
machine-readable identifiers, including Ethereum addresses, Swarm and IPFS content hashes, and other identifiers.