The aim behind the concept is to bring brands and companies closer for more aligned interactions. It's quite counter-intuitive but we'll create a "Defensive Marketing" channel as an opportunity for them to engage with their end-customers and be part of these conversation online about experience with their products & service. This will effectively provide them the chance to defend their reputation and manage their image in a genuine manner and in a public way.
It has been proven that an individual complaining online, that is then taken care of (and maybe eventually) and got his complaint resolved is far more inclined to turn into a praising customer (than a satisfied customer in the first place). In the same process the brand has the chance to show to others their engagement and care of end-users.
So on a psychological level it means that you-as a customer- you are important, your voice is valued and your experience/opinion matters.
Regarding other solutions out there today, I think they are well serving their own purpose like Yelp for local and others for more specific consumer reports. But Blacklist is focused on reacting and impacting on the brands & products experience that consumer have; anywhere anytime from any of their web-enabled device.