Stealth addresses are an important part of Monero's inherent privacy. They allow and require the sender to create random one-time addresses for every @transaction on behalf of the recipient. The recipient can publish just one address, yet have all of his/her incoming payments go to unique addresses on the @blockchain, where they cannot be linked back to either the recipient's published address or any other transactions' addresses. By using stealth addresses, only the sender and receiver can determine where a payment was sent.
To read how Monero prevents tracking coin history (untraceability), see @ring-signatures.