This is a bit over my head but I am intrigued. Can someone give a few examples of what this would let you accomplish and how it differs from current methods?
From what I've seen, they're making function hooking as easy as possible, by exposing it simply in a language plenty of developers are currently familiar with (javascript). Previously, it would take assembly code or c++ to accomplish this.
As to what you can do with this; since a program basically consists of logic (function calls) + data, you can change any behavior of a program by modifying the function calls and return values. For example, I have previously used these techniques to extend MSN (Windows Live) Messenger to support third party chat networks (Facebook, Google Talk), even though the program didn't expose any APIs to extend functionality (but by simply hooking and injecting data into network calls such as recv and send).
Interesting. This reminded me of old-time cracking methods. One tutorial (which I unfortunately can't find now) taught how to add functionality to an application. The tutorial used notepad.exe as an example, and after following, you added line numbering (at the left of the text-area and an entry in the menu-bar to show/hide it.
In those old times, this was done using a combination of W32dasm, SoftIce and Hiew ( a hex-editor that allowed you to view the instructions in a PE exe file).
The most impressive crack of this type I remember seeing was one where the "demo" version of a 3D-modelling program did not have the "Save file" routine (it was completely absent from the exe) and which was implemented as part of a crack (including GetSaveFileName dialog and all). That was some amazing stuff there.
If I understand correctly, this program offers a 'dedicated' process to achieve similar functionality.
