iOS 6 developer betas are distributed by Apple as a way for their registered developer communities to test out the OS across devices prior to a full scale launch. These betas are usually distributed among those registered developers who have a $99 per year registration account with Apple.
However, it appears that some of these registered developers are in it more for the commercial reasons rather than coding. Apparently some of them have been reselling these pre-launch betas to private users for a small fee. How does this work? Every registered developer gets backdoor access to activate up to 100 Unique Device IDs (UDIDs) for their account. That means for every account, they can sale the pre-launch beta release to 100 different customers. Once they used up their quota they simply went ahead and registered another account to carry on their business interests. Some of them have done pretty good with sales reportedly in excess of $75,000.
This had been going on for some time now and in spite of the fact that Apple knew about these practices they did not bother to do anything about it. After Wired published a story listing names of the services that offered such iOS 6 betas for a price, it seems that Apple has finally realized enough is enough and started taking this issue seriously. MacStories have been following this news for a while and they have noticed that many of the services which were originally reported by Wired are no longer available. Apple has been taking these sites off, wielding the stick pretty harshly.
A few of the site owners have confirmed on condition of anonymity that their sites were taken down following complaints by Apple about the legality of this whole deal and the copyright infringement that these service owners are engaging in.