Mmmmm, this shows demand and future increasing price aversion.  Sure sounds like a "bubble" to me.

http://cmegroup.mediaroom.com/index.php?s=43&item=3161

CHICAGO, June 15, 2011 /PRNewswire/ -- CME Group, the world's leading and most diverse derivatives marketplace, today announced it had reached three consecutive records in open interest for its benchmark Henry Hub Natural Gas futures contracts. These contracts are listed by and subject to the rules of NYMEX.

Prior to June 10, the previous record for Henry Hub Natural Gas futures open interest was 1,004,801 contracts set on May 4, 2011.

As the world's leading and most diverse derivatives marketplace, CME Group (www.cmegroup.com) is where the world comes to manage risk.  CME Group exchanges offer the widest range of global benchmark products across all major asset classes, including futures and options based on interest rates, equity indexes, foreign exchange, energy, agricultural commodities, metals, weather and real estate.  CME Group brings buyers and sellers together through its CME Globex® electronic trading platform and its trading facilities in New York and Chicago.  CME Group also operates CME Clearing, one of the world's leading central counterparty clearing providers, which offers clearing and settlement services for exchange-traded contracts, as well as for over-the-counter derivatives transactions through CME ClearPort®. These products and services ensure that businesses everywhere can substantially mitigate counterparty credit risk in both listed and over-the-counter derivatives markets.