This company sold a Certificate that allowed a MITM attack. They assure that they will not do that again in the future but this is a fundamental breach of trust that should lead to a removing of their root CA in the Mozilla root store. You may argue that many companies are installing their own root certificate in the browsers that are used inside their company that allows basically the same MITM but this case is different since a user of that affected network will assume that a encrypted connection from his own hard/software is secure. Their press release: http://blog.spiderlabs.com/2012/02/clarifying-the-trustwave-ca-policy-update.html
*** This bug has been marked as a duplicate of bug 724929 ***