I sent the coins to my Bitcoin Blender deposit address. It says it needs 6 confirmations, the transaction has 50. I also see other transactions going to the same mix address. Is this site a scam?
Probably. Could you link the full URL?
If you used any site other than the "official" one, which can be found in the links down below;
ANN:
https://bitcointalk.org/index.php?topic=436467.0Their campaign thread:
https://bitcointalk.org/index.php?topic=1633979.0,
it's more than likely that you indeed got scammed. (Or phished rather in this case)
There's no way really to get your money back if that's the case.