The nature of the ETF industry has lead smaller firms to introduce unique products such as the Claymore/Arca Airline ETF ( FAA), the Claymore/MAC Global Solar Energy Index ETF ( TAN), the WisdomTree Dreyfus Emerging Currency Fund ( CEW) and the WisdomTree India Earnings Portfolio ( EPI). Decisions by dominant players such as Vanguard and Fidelity to slash fees on specific products could compromise these smaller ETF providers' ability to compete if the large brokers begin to offer competing products. Right now, the greater risk is than investors may limit themselves to a single ETF provider. Over the nearly two decades that ETFs have been in existence, close to 1,000 different funds have been launched, proving investors with a plethora of opportunities to expand their portfolios into facets of the market previously unreachable. However, with brokerage firms now starting to adapt commission-free plans to keep customers in-home, the possibility of pigeon-holing an investment strategy becomes greater. As the cost of trading plummets, trading fees become an increasingly smaller share of costs. For small investors who make a lot of trades, it can still be hefty, but all in all, this is a shallow moat that investors should be willing to cross. -- Written by Don Dion in Williamstown, Mass.