PPC/XPM mechanisms are not just derivatives of BTC but have completely different mechanisms to BTC and each other.
Accordingly they are Class Currencies.
Subclass currencies are one that are not derived from the overarching class concept
List of class currencies BTC is a class currency being the first of its type and POW secured
PPC is a class currency POS secured
XRP is a class currency (Ripple consensus)
List of sub class currencies XPM is a POW subclass class currency twin conjecture
NXT is a subclass/Class currency being POS however this is border line as it maybe a class as it has many other different features
Blackcoin, subclass of POS
BitShares family:Need more info, likely POS subclass, and perhaps DPOS? (is it?) this may also be borderline and a class currency for reasons simlar to NXT
http://bitshares-x.infohttp://bitshares.orghttps://bitsharestalk.orgLTC is an alt of Tenebrix etc, subclass POW, scrypt.
Under Dev
emunie is a class currency
NEM POI, this looks to be a new class curency.
post any other class / subclass currencies in this thread
