I have tested it myself on the big 4 just now (Firefox, Internet Explorer, Chrome, Safari). All work at this time.
If you have a problem in the future, however, I would suggest trying www.11thhour.net
. It provides the same access to the forums as mafiascum.net. It, however, is powered by the Power of the 11th Hour and the Hope and Faith of the mafiascum community (plus electricity). Compared that to mafiascum.net, powered by mith's presumed forced labor, a source which will assuredly be growing more fickle as news of the freedom pounding at the gates reaches their ears.