Let's say you write a PDF and want to sell it, but you also want to prevent the possibilities of group buys as much as possible, how would you do this? Is there a way to generate one-time-use activation keys for PDFs so they can only be activated on one PC? Sort of the same way that PC games work
There are some services that do that , but basically they wrap it up as an exe file which I assume you're trying to avoid. clicklocker.com (I think that's the url) and whiteknight comes to mind if my memory serves correct. If not there's some inexpensive HTML compilers that will do the trick, but you may lose some of the Mackintosh crowd and a number of others who won't download exe's. You could password protect the pdf file, but passwords can be "shared" as well and IMO it's more trouble then it's worth with customer support. Then there's real pdf protection, Adobe offers it, but several years ago it was $5,000 and I've bought close to a thousand ebooks, but have never seen it used even for $97 ebooks. As for locking it to a computer try one of the services mentioned, but I think it's a subscription. Or use an HTML compiler like ebookcompiler.com But unless it's REALLY sensitive I'd avoid trying to protect it at the cost of discouraging buyers.