> I want JQuery 1.2.3. I ask your computer [...] returns it to my computer Good ! Now I know you have JQuery 1.2.3, which is vulnerable to exploit XYZ, which I

> I want JQuery 1.2.3. I ask your computer [...] returns it to my computer Good ! Now I know you have JQuery 1.2.3, which is vulnerable to exploit XYZ, which I can now use to target you. This is one reason why apt-p2p and things like that can't be deployed in large; it's way too easy to know what version of what packages are installed on your machine.