DPOS seems to refer to completely two different things.
Firstly, there is BitShares' DPOS system which stands for "delegated proof of stake". This is the most common meaning of "DPOS" and is the one that most people probably think of and are referring to:
http://wiki.bitshares.org/index.php/DPOS_or_Delegated_Proof_of_Stake
Then there is also something called "dynamic POS" which OP mentioned. Dynamic proof of stake (also called DPOS) seems to be a variant of proof of stake used by the lesser known altcoins Positron and Isotope. I'm not sure how it differs from traditional POS but it looks like it involves stake rewards which change over time depending on which blocks are mined:
http://bitcointalk.org/index.php?topic=1021029
http://bitcointalk.org/index.php?topic=1039891
Firstly, there is BitShares' DPOS system which stands for "delegated proof of stake". This is the most common meaning of "DPOS" and is the one that most people probably think of and are referring to:
http://wiki.bitshares.org/index.php/DPOS_or_Delegated_Proof_of_Stake
Then there is also something called "dynamic POS" which OP mentioned. Dynamic proof of stake (also called DPOS) seems to be a variant of proof of stake used by the lesser known altcoins Positron and Isotope. I'm not sure how it differs from traditional POS but it looks like it involves stake rewards which change over time depending on which blocks are mined:
http://bitcointalk.org/index.php?topic=1021029
http://bitcointalk.org/index.php?topic=1039891
Interesting.
How many kinds of POS are there?
I just saw a coin in the altcoins mentioning vPOS...
Peercoin uses minting (which uses coin age), NXT uses transparent forging (where the next forger is known in advance), BitShares uses delegated proof of stake (DPoS) where 101 delegates are elected to process transactions, Reddcoin uses proof of stake velocity (POSV), and NEM uses proof of importance (POI) where factors other than just the size of your balance alone are also taken into account when determining staking probability.
There are probably others that I have missed but I think these are the major ones.
And to think that I thought that I started understanding POS
Also forgot to mention that they were pretty much developed in that order too, with Peercoin being the first PoS coin and NEM being the newest (well technically, PoI more of an off-shoot of PoS rather than pure PoS and had already been in development for months when it was launched but you get the idea).
The basic idea behind PoS is actually quite simple. Each coin is like a minature mining machine that solves blocks just like the way a real miner does. The more coins you have, the more blocks you can generate and the more coins you can get. Most of the above are simply variations of this basic theme.