No, it wasn't a new concept, but it practically was. Tenebrix came afterwards. Solidcoin was a scam and I0Coin, Ixcoin and Litecoin all came out within a month of each other.
No
Tenebrix launch: September 26, 2011, 12:09:44 AM
Litecoin launch: Thursday Oct 13 2011, 03:00 GMT