There are lots of FAQs on that site, but the first few seem concerned with how to buy shares in the company or asking for photos of the Chief Exec in the factory: how odd. A better set of FAQs would surely be, "What is an Ecat?", "What fuel does it need?", etc etc.
As a consequence, I don't know if this Ecat thing claims to have achieved cold fusion or not. But yes, cold fusion is one of physics' holy grails. Nuclear fusion produces huge amounts of energy, and it's clean too (no nasty radioactive by-products IIRC). The problem: it takes mind-boggling quantities of energy to make it occur (e.g. you'd need to heat up the fuel to some crazy temperature). Now, if it could be achieved without the huge energy input (with "cold" inputs), then you'd get all that energy out without having to put stupid amounts of energy in.
It's never been successfully demonstrated on Earth. The Sun is a fusion reactor, but that is super-hot and is under huge pressure too.