In the world of pirates stealing software, one common technique is to download a trial or demo, patch it and upload this as the stolen version of a piece of software or game. This makes me think: if I sell software one day, it would be possible to set up a custom server, that builds a specific package, personalised to the user, when he downloads a trial. For example, the binary would contain identification numbers and checksums (like a signature using my private key), etc.
This way, if somebody cracks a trail of some software of mine, and uploads that, I could download that, and extract the identification of it. Would that be of some juridical significance to sue the cracker? Compare it to somebody that would buy music on iTunes, and be stupid enough to upload it with his name still in the files. The only difference is that I would try to hide this information, so it's not that easy to spot.
Such information is most likely to remain in the binary, since this has nothing to do with the trail vs full version code in the binary. Or in the least significant bit of the red channel of a PNG image included in the software, for example. A cracker would most likely never notice this, unless he downloads the software multiple times, and bindiffs the packages. If he does that, he could throw try to throw out the information (and optionally a check procedure in the binary that verifies if the data is still there and valid). Then the cracker would have successfully removed the identification information.
I feel like this is an interesting thing to work on and be developing such a thing, but if this isn't going to help me in any way to protect my software, or sue the crackers, then it's probably not worth all the effort.