That's because Darkcoin stole the name from the Dashcoin community.

The ironic thing is Dashcoin, which is based on the superior Cryptonote protocol, offers much better privacy/fungibility/anonymity than anything Darkcoin ever implemented.

Dash uses a bastardized, broken, cargo-cult's "bad crypto" bamboo version of CoinJoin.

Dashcoin uses proven/working/legit crypto in the form of stealth addresses and ring signatures.

Dash's off-chain, online DarkSend takes forever as participants are at the mercy of current conditions (ie how many others want to mix at the moment) and trusted 3rd party Masternodes' security.

Dashcoin's on-chain, offline mixing is instant, as it uses the entire set of all previous transactions for mixing, and so does not require trusted 3rd parties nor liquidity providers.

Of course the DashHoles around here will shoot the messenger and attack me for stating those facts, rather than attempt to refute them.

Perhaps they'll start to listen when Dashcoin's market cap exceeds Dash's (which at this rate won't be long from now).   

More info here: http://monero.stackexchange.com/questions/943/is-dash-based-on-cryptonote-or-coinjoin