Metals Go Mainstream

Of the seven new ETFs, three provide exposure to a single commodity while the rest track a basket of two or more commodities. There's the PowerShares DB Oil Fund (DBO), which follows the performance of light sweet crude oil; the PowerShares DB Silver Fund (DBS), which reflects the price of silver; and the PowerShares DB Gold Fund (DGL), which tracks gold.

ETFs on the market that provide exposure to gold and silver include the streetTracks Gold Trust(GLD Quote), the iShares Comex Gold Trust (IAU Quote) and the iShares Silver Trust (SLV Quote). These products don't hold futures contracts but instead hold the actual metal in a vault.

There also are other ETFs that track energy, such as the United States Oil Fund LP(USO Quote), which invests in energy futures contracts, and others that provide broad-based exposure to commodities, such as the PowerShares DB Commodity Index Tracking Fund(DBC Quote) and the iShares GSCI Commodity-Index Tracking Fund (GSG Quote).

The ETFs that represent baskets of commodities include the PowerShares Deutsche Bank Agriculture Fund (DBA), which tracks corn, wheat, soybeans and sugar; the PowerShares DB Base Metals Fund (DBB) , which provides exposure to aluminum, zinc and copper; the PowerShares DB Energy Fund (DBE), which tracks light sweet crude oil, heating oil, Brent crude oil, RBOB gasoline and natural gas; and the PowerShares DB Precious Metals Fund (DBP), which tracks gold and silver.

According to Greg Newton, who runs the Naked Shorts blog, the agricultural ETF will generate interest because of many developments in the space -- for instance, demand for corn, which has risen due to the expansion of corn-based ethanol in the U.S.