Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.
Rig Count Interactive Map by Baker Hughes, an energy services company.
Shale Sheet Fracking, a Youngstown Vindicator blog.
The Ohio Environmental Council, a statewide eco-group based in Columbus.
Earthjustice, a national eco-group.
People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.
Concerned Citizens of Medina County, a grass-roots group.
No Frack Ohio, a Columbus-based grass-roots group.
Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.
Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.
Allegheny Front, environmental public radio for Western Pennsylvania.
The Economist has a column on whether the U.S. experience in fracking can be repeated elsewhere in the world.
The story starts: "SCOTT Stevens of Advanced Resources International gave an interesting talk at a Hong Kong conference this week on the future for shale gas supplies. This is one of the most interesting (and encouraging) developments of the last few years for the US economy; a plentiful source of cheap energy.
"... Mr Stevens pointed out that the sudden emergence of shale has had forced the US price down from $30 to $2.80, below the marginal cost of production, which he estimated at $4-$5. Supplies may last for more than 100 years. Shale oil may also be useful but not on the same scale - perhaps another 2m barrels a day by 2020.
"But the US has been exceptionally good at exploiting its supplies and has more favourable geology than other countries"
Read the whole thing here.