Following the May 4 shocking Unabomber billboard campaign  and subsequent departures of more of Heartland's corporate donors , Heartland was likely heartened to add the Illinois Coal Association  as a new Gold Sponsor for its forthcoming ICCC-7 "climate" conference. Although ICA was not on the 05/09/12 sponsor list , it joined the usual collection of thinktank sponsors no later than 05/14/12 , Maybe the billboard finally convinced them to come out publicly?
In the 2012 Fundraising plan  p.24, Murray Energy gave $100,000 in 2010 and was expected to give $40,000 in 2012. Its subsidiary , The American Coal Company is a member of the ICA , along with Peabody Energy and Arch Coal, among others.
In the PDF at Fake science, fakexperts, funny finances, free of tax , pp.84-85 I showed Heartland's Environment and Climate News to have consistent views on some topics:
Negatives included the EPA (2160 mentions), renewable (761), wind farm (333), wind power (277), solar power (209), wind turbine (188).
Mercury (941 mentions) was generally viewed as OK, in fish or the environment, unless it came from CFLs. Coal (935) was often praised.
In any case, the ICA's post-billboard sponsorship of ICCC-7 is a bold public leap.