Here is some good info on the BDI for you Bill.
The BDI is one of the purest leading indicators of economic activity. It measures the demand to move raw materials and precursors to production, as well as the supply of ships available to move this cargo. Consumer spending and other economic indicators are backward looking, meaning they examine what has already occurred. The BDI offers a real time glimpse at global raw material and infrastructure demand. Unlike stock and commodities markets, the Baltic Dry Index is totally devoid of speculative players. The trading is limited only to the member companies, and the only relevant parties securing contracts are those who have actual cargo to move and those who have the ships to move it. 
The run up from 2005 to the end of 2007 was primarily due to Chinese demand for industrial precursors to production and its shift from coal exporter to importer. There was also a shortage of supply for dry bulk cargo ships and a large backlog at shipyards. The combination of these two factors caused a nearly 200% gain in the index. From June through October 2008, the index lost 85% of its value as demand for shipping plummeted. This is due to a simultaneous convergence of several factors. Chief among these is the rapid slowdown in the "global growth" phenomenon. In addition to this, credit has been nearly impossible to get for the purchase of goods and the payment of time charters on the vessels.
This index is one of the purest leading indicators of economic activity. It measures the demand to move raw materials and precursors to production. Consumer spending and other economic indicators are backward looking, meaning they examine what has already occurred. The BDI offers a real time glimpse at global raw material and infrastructure demand. This could also be gleaned from looking at commodity prices, but there are substitution effects and futures contracts that make it difficult to interpret the impact of commodity price fluctuations. Additionally, nearly all commodities are seeing severe increases in prices in 2008 regardless of supply situations as investors seek to hedge their inflation exposure with hard assets.
Dry Bulk Shipping Stocks
When an investor buys a dry bulk shipping stock, they are effectively buying into the Baltic Dry Index. The amount of exposure depends on the individual stock. Some companies, such as DryShips (DRYS), have most of their ships contracted out at the spot Time Charter Equivalent. This means that the contracts are directly correlated to the daily price of the BDI. Thus, their revenues are directly tied to the index. In times of increasing prices, this set up will yield greater profits for the shipper. Other companies, such as Diana Shipping (DSX), have contracts set at the period Time Charter Equivalent. This means that they enter into a contract, usually 2-5 years in length, which pays a fixed daily rate. This set up provides less volatility, hedges risk against falling BDI rates, and guarantees cash flows.
A lot of info on these wiki's, just be careful and confirm the info for yourself!!