Boostria takes the concept of word of mouth marketing and gives it the kind of boost that only the Social Web makes possible.
In general terms, what users of this new marketing tool can do is to invite people who have hired their services to write a comment in which the better points of the company are highlighted. These comments are kept purposefully short - they can include no more than 200 characters and two pictures. And once they have been written and posted, Boostria takes care of spreading and promoting them all over specifically-selected sites and blogs (IE, sites and blogs that have something to do with what the actual company that is being reviewed does).
In this way, a true network of recommendations can be built. People who are just getting started will no doubt find such an alternative to other forms of promotion appealing. It is not that it could replace any of these, but as far as complementing such services go, Boostria is more than fulfilling.
It is an intelligent development of the concept of word of mouth, and one that suits the dynamics of the Internet just perfectly.