Disclaimer
I'm using my alt, so the "you work for the competition"-argument can't be used. I've used and/or tested several mixers, it's not as if I suspect all of them to be scammers.
This is not a scam accusation (yet), I have no evidence that anyone got scammed (yet). I think it's worth discussing though.

My gut feeling
MIXERCOIN (username: mixercoin) gives me the same feeling BITMIXCOIN.IO (Trust: -64: -6 / +0) did a year ago. They claimed to own 2000+ Bitcoin, but couldn't prove it. Eventually, that mixer pulled an exit scam and stole well over 16 Bitcoin before their webhost took them down.

Serious questions are evaded
MIXERCOIN follows a similar pattern: claiming to have very high (in this case even unlimited) funds, but refusing to sign a message. This is how they respond to valid concerns:

Quote from: mixercoin on October 08, 2018, 05:07:08 PM

Quote from: LoyceMobile on October 08, 2018, 05:03:15 PM

Quote from: mixercoin on October 08, 2018, 11:14:00 AM

that maximum amount of the mixing has not limit

That's only possible if you own 50% of all bitcoins. I don't believe that, so it's not possible.
Can you at least sign a message to prove ownership of substantial funds?

We own enough bitcoins. Question to you. Do you have money?

Playing dumb
They pretend not to know how to prove ownership of funds.
Laughing at valid concerns is what I expect from a scammer, not from a legit business:

Quote from: mixercoin on October 08, 2018, 06:23:03 PM

Quote from: stomachgrowls on October 08, 2018, 06:13:20 PM

Quote from: LoyceMobile on October 08, 2018, 06:02:08 PM

So you're saying you run a mixer but don't know how to sign a message?

Thats the dumbest thing for a mixing service who didnt even know how a sign message works. Shocked

So far, only I have a smile when I hear that 0.01 bitcoin are a large amount
The best proof is not words but the result. Do mix on 0.01 btc or too much for you?

Even if mixing a small amount would work, that doesn't prove it's not going to be a selective or exit scam.

Spam
They're spamming many local boards with Google Translated posts, which isn't allowed. I've reported some of the posts, and some are gone already, so I've archived it.

The problem
It can't be proven until they scam someone. Any Newbie that asks for a no collateral loan, quickly gets tagged, because most of them are scammers. Meanwhile, anyone can promote their mixer, even though many of them are owned by scammers.
BITMIXCOIN got tagged with red trust after they scammed 16 Bitcoin, and the victim sent me his Letter of Guarantee. MIXERCOIN doesn't even have a Letter of Guarantee, so there will never be any conclusive evidence.
So far, I haven't tagged anyone based on speculation, and I don't want to start that now. On the other hand, I'd hate to see another scam mixer make an innocent victim if that can be prevented.