The network charges a small fee when you send a transaction or register an account. These all contribute to the daily income.
The 101 delegates I mentioned earlier that maintain and process the transactions are paid a portion of these fees, this is the daily expenses. The left over amount is burned.
Whenever BTSX is burned, you now own a bigger % of the total. This is the dividend.
(This is the opposite of Bitcoin that charges you via inflation paid to miners. Whenever new Bitcoins are created (The opposite of burned) it means that you now have a smaller % of the total.)
(Burning the BTSX has the same effect as distributing those BTSX evenly to everybody based on their holding)
You will probably not be able to buy shares in listed companies like overstock for a while. http://bitshares.org/overstock-to-cryptostock/
As exciting as it would be to see Overstock or another company issue a crypto-stock in the next few months, I think it would do far more harm than good. Forging blindly ahead with issuance of a crypto-security before taking the time to make sure regulatory and business objectives are met could create confusion and distorted public perceptions, thus substantially delaying the day that crypto-securities are widely accepted among market participants. Careful evaluation of the various issues and risks from regulatory and business perspectives can help ensure that the amazing potential benefits of being able to issue shares on a crypto-ledger are realized.
But you can already trade BitAssets. If you go to the markets section you can go long or short BitUSD, which aims to track around the price of a USD.