can you nutshell it?
You take something that's normally nearly indistinguishable (e.g. 1 USD bills) and arbitratrily declare some of that "special", "tainted" or "colored".
For example I have a 1 USD bill with the serial number 1234567890 and I declare that I will give anyone who hands me this exact bill in the future 100 USD, then I spend it/auction it/otherwise get rid of it. Everyone who does NOT know about the new value I gave to that bill still thinks it's an ordinary 1 USD bill, not worth 100 USD and might carelessly spend it. Also if there were no way to know it's exactly THIS bill (no tracking/serial number) it also wouldn't work, as I wouldn't be able to tell if I have to give out 100 USD back if someone hands me an unmarked bill.
Colored coins work similarly, you declare that some coins are "special" to you and represent shares or whatever. This special value or contract does not show up anywhere in a block chain (other than transactions with these coins) but they can be traced due to the public nature of the block chain. So if I then publish "I started giving some special value to THIS coin, then used it in this transaction etc." people can track which address holds these coins and see if they own any. Since the coins are potentially worth more than other coins of the same denomination (in the example: the 1 USD bill would be worth 100 USD minus the risk that I might not honor my contract) one could for example trade in the same chain for these special coins (in the example: someone buys the special 1 USD bill from someone else for 50 USD).
As these transactions take place in a block chain and not for example on a stock trading platform (e.g. A transfers to B 1 special coin and gets from B 1000 "normal" coins in return) you can cut out the middle man. Also you can create more arbitrary contracts. Issues mainly include mixing "normal" and "special" coins and making sure you don't accidentially spend your special coins like normal ones (in the example: buy an ice cream with the 1234567890 1 USD bill). This is why the ArmoryX software is being written, to take care of this and some other issues.
Thanks, this may take a bit to sink in
but If I follow you, it allows capital raising, minus a lot of stock exchange fees, eg you just need to put the listing on a board and off you go.
also serves a a means to distribute dividends to said addresses as you can see where they are
so it sort of piggy backs the stock market onto the back of the existing BTC structure.
I would have thought that such a thing if it works would be quite the boon and worth a couple of hundred/thou BTC to get the
client and market watching software together, time to do a capital raising over at crystok et.al, so you can bootstrap out of having to do a capital raising (sort of like how you had to boot early computers when you think about it).