Quora is a community web site in which users can contribute by asking and answering questions.
Thus the Question and Answer site, Quora, aims to build a great knowledge database whereby real internet users share their experiences, information and knowledge.
In addition people are allowed to ask questions free.
Initially the web site does not allow any one to make accounts. This is the month of October 2011, and the company is following the same policy.
If you want free invitation for Quora accounts please leave email addresses in the comments below i will send you the invitations.