That poster on /r/bitcoin admitted that the latest DarkSend is indeed decentralized but pointed out that the specs don't mention anything about signing. As mentioned in gmaxwell's original post (
https://bitcointalksearch.org/topic/coinjoin-bitcoin-privacy-for-the-real-world-279249), blind signatures are needed to truly prevent anyone from learning the sender-receiver mapping. Does DarkSend implement blind signatures? If not, are there plans to introduce it?
Evan isn't doing a straight coinjoin. He had an epiphany and realized a simple but wholly effective solution, which you can see on the first page. It does require, at the moment at least, a master (wallet I believe) to function as intermediary or the "pool pot"
The use of darksend starts off with denomination of your balance, which means your coins are grouped and accounted for in fresh transaction numbers in denominations of 1000, 100, 10, 1, .1, .01 etc... so you can't see, when a transaction starts, where the original coins came from. They go into the pools without a history and with a random single use account number (used only once, the change will have to be re-denominated in the future to be a part of a rounded amount (100, 10, etc...) and it's history will once again be wiped.
Once the payee's money leaves the pot to go on it's way, the "change" is sent back to the original sender using another random throw away address. There is no way to know what happened and who sent what unless you know the secret (were the sender) then you can see your coins being transferred (you still won't know which of the 100's 10's etc... was yours though)
I hope if there is a hole to be found that it's found sooner than later, though!