NEW YORK ( TheStreet) -- The size and scope of ETFs is growing rapidly, as the adaptable funds take aim at an even broader audience. Among the top most-active symbols in the market today are ETFs like the Financial Select SPDR ( XLF), SPDR Trust ( SPY) and iShares MSCI Emerging Markets Index ( EEM), evidence that these funds have taken more than a foothold.Originally touted as "mutual fund alternatives," it has now become clear that ETFs stand on their own and have aim beyond the mutual fund industry. The success of individual country funds like Market Vectors Russia ( RSX) and fixed income products like iShares iBoxx $ Invest Grade Corp Bond ( LQD), illustrate the range of the ETF product line. While some funds, like the Vanguard Value ETF ( VTV) and the iShares Russell 3000 Value Index ( IWW), don't seem like a far shot from their mutual fund peers, commodities and bond offerings seem to be aiming at strategies that mutual funds can't. Due to their structure, ETFs can provide daily trading strategies, like Direxion's Daily Financial Bull ( FAS), to sophisticated investors, while offering physically backed gold funds, like SPDR Gold Shares ( GLD), that can be traded intraday by a broader audience. Since the funds are seeded by market participants, they have continued to debut on stock exchanges across the globe, even as equity IPOs remain lethargic. A recent article in Barron's realistically notes that the 40% annual asset-growth rate of ETFs over the past 10 years will likely slow to around 20% to 25% over the next three to five years. Tax efficiency and transparency are among the reasons that investors have flocked to passive exchange-traded products. As investors become increasingly wary of hedge fund managers, these passively indexed products will become even more appealing.