It almost always works for some reason.. my best guess is that sites allows these crawled links to see the full content because doing otherwise would harm their SEO.
So from publisher's perspective, they are getting more SEO by pay-walling!
A leading trading site management company "bit coin (BTC = Bitcoin)" virtual currency on the Internet, the 20th, I had described the company has lost the bankruptcy in February "Mount Ngoc, Inc." The (Tokyo) Of the approximately 850,000 BTC, has announced about 200,000 BTC has left.
According to the lawyers of the company, the 7th of this month, the company was using previously in June 2011, and found the place of examination of the storage location on the net called "Wallet" and (wallet).
February 28, when it is filed for Civil Rehabilitation Law in Tokyo District Court, the company describes a total of about 850,000 BTC corresponding to almost all to be held has been lost.
Edit: antonius has posted the content above: