Reviews Posting is done by the clients of a company to recount their experience. These postings are very much useful for the prospective clients.
"I have much to say why my reputation should be rescued from the load of false accusation and calumny which has been heaped upon it."- Robert Emmet
Reviews are posted about a company by its satisfied/dissatisfied clients. Though sometimes these happen to be just the honest representation of the experience that clients have for a company, but often it is used to bring down the reputation of a company. A rival company takes the shelter of posting to show a reputed company in bad light.