The DAO token is built on ethereum. 

The ICO - or initial coin offering - raised $5.5million to acquire the 85% of the DGD tokens. 

Digix DAO is a "Decentralised Autonomous Organisation" - DAO's are a nascent idea and are therefore not a fully proven concept. The Digix DAO tokens give holders the rights to vote on how funds earned by the DAO are spent and act like shares in a traditional Company. 

The DGD tokens give users the right to earn profits from the trading of DGX tokens - which are tokens backed 1:1 with a gram of gold. The DAO or DGD tokens earn a commission fee based on the number of trades of the DGX tokens. holders of the tokens can vote for 

There are costss for the DAO so headline commission is not equal to profit. The cost come in the form of storing the gold and auditing its veracity. This is where the role of voting rights come in as holders of the tokens can vote who they want to audit the gold. 

If the DAO runs out of funds the founders can propose to raise more tokens in an offering which requires a special majority of voters to agree to. 

The initial offering raised $5.5million for 85% of the tokens. The other 15% were rewards for developers and founders - a premine of sorts.