Sandboxing is the technique of enclosing your application so that it cannot reach out to the rest of the system (go outside the self imposed sandbox). This process will prevent malicious code from accessing critical system files, or in reality, anything outside of the Adobe Reader application itself. Sandboxing has been a recent security trend in software. Google Chrome utilizes sandboxing for the various threads it creates (each representative of a tabbed browsing session), and explains sandboxing in its Google Chrome comic. The implementation of this is something that can not come soon enough for Adobe's targeted software.

PDFs are increasingly a part of enterprise software, and thus, such a juicy target for malicious code. There are alternatives to Adobe Reader. However, the large acceptance of Adobe's Reader, and the lack of a strong and established competitor makes this implementation more difficult to pull off. At this point, however, it seems like waiting is the best course of action. Interviews with Brad Arkin, Adobe's Senior Director of Product Security and Privacy, seem to suggest that this new version with security perks will be available sooner than later. If you're going to take the time to do an enterprise level change in software, you might as well hold off for a little while longer and spend that time upgrading from Adobe Reader version 9 to version 10.