antminer u3 what can they mine? noob alert
You can only mine altcoins that use the SHA 256 algo.


BTCitcoin(Its funny to write about bitcoin bcoz everyone know this)
21Coin (21)
Peercoin (PPC)
Namecoin (NMC)
Unobtanium (UNO)
Deutsche eMark (DEM)
Betacoin (BET)
Bytecoin (BTE)
Joulecoin (XJO)


10.Devcoin (DVC)

11.Ixcoin (IXC)

12.Terracoin (TRC)

13.Battlecoin (BCX)

14.Takeicoin (TAK)

15.PetroDollar (P$)

16.PremineCoin (PMC) {Premined, Mine only tx Fees}

17.Benjamins (BEN)

18.Globe (GLB)

19.Unicoin (UNIC)

20.Snowcoin (SNC)

see https://bitcointalk.org/index.php?topic=482002.0