Over the past several years, exchange-traded funds have enjoyed a tremendous surge in popularity, passing many major milestones as they were embraced by retail and institutional investors alike.

Once comprised solely of “plain vanilla” products tracking well-known equity indexes, the ETF industry has evolved at an incredible pace in recent years, and now offers investors exposure to nearly every corner of the investable market. Along the way, we’ve seen brilliant innovations (such as leveraged ETFs, “intelligent” ETFs, and actively-managed ETFs, just to name a few) and a plethora of new fund launches (at last count, there were 850 ETFs in the ETFdb Database).

The number of US-listed exchange traded products increased by 13 in June after dropping by 14 the prior month. The total value of shares traded was $1.5 trillion, just below May’s $1.505 trillion.

June brought the introduction of 16 new products, consisting of 14 ETFs and two MacroShares. One ETN and two MacroShares were delisted. The total number of listed products at the end of June stood at 843 (757 ETFs, 2 MacroShares, and 84 ETNs), two less than the 2008 year-end total.

A week after folding the second incarnation of its unique up/down crude oil funds due to the failure to attract sufficient investments, MacroShares burst back on to the scene with the launch of two new exchange-traded products (they’re not technically ETFs). The MacroShares Major Metro Housing Up (UMM) and Major Metro Housing Down (DMM) began trading on Tuesday. While these funds are attracting significant attention because of their unique strategies and exposure, they are also being greeted with a fair amount skepticism.

According to their fact sheets, DMM and UMM will track three times the cumulative percentage change in U.S. single-family home prices, as measured by the S&P/Case-Shiller Composite-10 Home Price Index. This benchmark is a frequently-monitored indicator of single-family home prices in ten major markets (New York, San Diego, San Francisco, Washington, D.C., Boston, Chicago, Denver, Las Vegas, Los Angeles, and Miami). After relatively steady appreciation since the early 1990s, this index has plunged over the last two years amidst spikes in foreclosures and freezing credit markets.