The purpose of the site, which can be found at www.horsesmouth.co.uk, is to build an online community where people who are experiencing difficulties with their job or their life can contact other people who have overcome similar problems.
Not launching until June, the site already has more than 1,000 registered users.
Rainey said: "This is a site that does something for the social good. It is less chaotic than a chatroom."
The site has a specially built search engine that, using data supplied by users when they register, allows pairings to be made quickly and effectively.
It is open to anyone over 16 years of age and the process is totally secure, with no real names, e-mail addresses or pictures permitted to be used.
There is a user-driven reputation system that, as well as rating a mentor, will also highlight those who misuse the site.
There is also a section devoted to helping people get ahead in their working life, from choosing or changing their career to offering advice on starting up a business.