If this already has been posted I apologize.  This news is strictly for Pennsylvania.  If you live outside the Commonwealth you are not impacted:

Dunham's Rule is being challenged in court.

Link to rule info

News

Your jeopardy lies with the possibility you might not own your mineral rights.   Challengers are asserting Marcellus gas is (in effect) a mineral.

It is possible in PA for landowners to own their O&G rights but not own their mineral rights.  Under Dunham's Rule, which has been precedent in PA for a long, long time, natural gas is not a mineral.  If the courts belatedly support the concept of Marcellus natural gas being (in effect) a mineral, then landowner had better own his mineral rights in order to lease land and collect bonus and royalty.

In the past, under Dunham's Rule, if you owned your O&G rights in PA you were in the tall alfalfa.  Mineral rights did not matter vis a vis Marcellus drilling, only O&G rights mattered.

If the challenge to Dunham's Rule stands [massive litigation is anticipated] you will still be OK provided you also own your mineral rights.  Otherwise . . well . . you could have trouble on your hands.

Good luck to all.