I reread the article, it is that good. However, one moment does seem extremely unusual. How does one go from being active on investment forums to securing a few million from very experienced investors. It is one of those one in billion occurences. I am sure Mike Burry would have done alright even without it, but still there must be more to the story. Hopefully, full book goes into more detail.
There is an online forum for value investors called value investors club.
In order to become a member, you have to submit an investment idea which is then evaluated. If it is good enough, you get in and become a member.
The forum was started by Joel Greenblatt, of Gotham Partners. What Greenblatt does is monitor the users on the site and gauge their abilities based on ideas... if their ideas are good enough he usually contacts them to make a seed investment so that they can start a hedge fund.
Pretty much any fund connected to Gotham gets the attention of other investors and it is usually pretty easy for them to scale up afterwards. e.g.: going from 0M --> 200M in just a few years. Its sort of akin to how companies funded by YC can sometimes have it easier when attracting VC funding.