This is a quote from presstab in the slack:
presstab
@dromund we are working on implementing zerocoin into Pivx. We are beginning the testing phase right now and things are looking good.
Huuuu, copycat copies another popular feature, lol.
FYI - no proof of stake coin has ever implemented libzerocoin as it was designed for Proof of Work.
So there is no coin to "copy" this from. PIVX will have a custom implementation of libzerocoin.
Also, zerocoin is a protocol.
https://isi.jhu.edu/~mgreen/ZerocoinOakland.pdf-------
I guess most don't know what libzerocoin means. It essentially creates a "zerocoin" layer between the end-to-end PIVX transaction where it completely severs the association between your transferred PIVX and the received PIVX during the transfer. It's like taking your cash (PIVX) to the casino, getting some chips (zerocoins), then changing your chips (zerocoins) back into cash (PIVX). Due to that, the 2 ends of cash (PIVX) transactions are no longer linked as different cash (PIVX) was provided from the casino (zerocoin pool). This allows 100% provable untraceable transactions. You still see the end-to-end transaction amount.
Now, some people might go "I don't care about my transactions being private. Why should I care?"
Well, you should care. What happens if there is a big arms/drgus dealings using your crypto of choice. (e.g. Bitcoin) Now, after they used it and then cashed it out etc, what happens you end up with those coins. Now, feds, nsa, cia etc etc can trace every one of those transactions as you know through the block explorer. Then they might knock at your door as they traced some of those coins being transferred to your coin address somehow. You might say I don't know anything about it, but there's clear proof in the block explorer where you did receive a portion of those "tainted" coins. and could be quite complicated for you to prove that you weren't part of that. But with every PIVX transaction going through the new upcoming zerocoin protocol, you won't have to worry about that as your coins will have a clean history. (It will be enabled by default so no one really needs to know how to use it etc, it just works)
FYI - No coin provides this kind of anonimity by default right now. Hence this is very big if PIVX devs can make this happen. It will be a first in crypto afaik.