By now, you've seen a lot of comment on this deal, ExxonMobil's first corporate acquisition in a decade, and the first grab of a super-independent since ConocoPhillips acquired Burlington Resources--that also was a predominantly natural gas play. I now count at least $53 billion for assets acquisitions, corporate mergers or joint ventures in shales, including ExxonMobil's deal, which will total $41 billion when accounting for the XTO debt assumed. Recall that in the past 18 months, XTO spent at least $11 billion snapping up primarily shale and tight-gas assets to build a strong platform for long-term growth. (See Oil and Gas Investor A&D editor Steve Toon's detailed treatment of this in the August 2008 issue, in a piece titled "Transforming XTO.") It seems the largest shale players have become the farm teams for the majors and national oil companies. The interest in shales continues: We hear from our sources that the China National Petroleum Co. (CNPC) is asking around, through the DOE, to have an independent host a tour of a shale operation. This fits in with the U.S.-China energy technology exchange program inked between the Obama administration and Beijing recently. The XTO deal sends sevral signals to themarketplace. The value of the shales as a long-term gas source has been validated by the savviest company out there: ExxonMobil is known for being conservative and taking its time, and making no big, bold move without first studying it to death. It implies faith in the long-term gas price outlook, and demand outlook. If any particular shale is not economic now, it will be some day. If EURs are in question, as they have been by some critics, that argument has been tamped down. The shale story will continue, and ExxonMobil will now have a hand in telling it. ExxonMobil has a lot on its plate around the world, from LNG in Qatar to spending a rumored $1 billion to fund a new purpose-built drill ship for the Arctic, to R&D on algae as a fuel source. That it decided to add natural gas shales to the portfolio says a lot. --Leslie Haines, Editor-in-chief, Oil and Gas Investor magazine