Here is a link to a discussion of a Telephony Denial of Service (TDoS) attack against enterprise FAX machines. This is yet another attack occurring because of WikiLeaks. Attackers have published some FAX numbers at enterprises, which do not support WikiLeaks. The attack involves call floods against these FAX numbers, so that legitimate FAXes can't be received.
This could be a very disruptive attack, if the attacker had access to many of the FAX numbers in a large enterprise. These FAX machines are essential for many financial or business transactions.