Recently we read that spammers and other crooks were offering "porn prizes" to people in return for CAPTCHAs interpretation. They're hoping to reduce the cost of their current strategy, which employs humans in low-cost labor zones.
That's the evil side.
The good side strikes back ...
... CAPTCHA, you will not be surprised to hear, is ubiquitous. Luis figured out that the little buggers are filled out about sixty million times per day by someone on the web. So, as the inventer, he first felt a certain amount of pride at having exerted such a palpable influence on modern life. But after a bit of reflection, and multiplying sixty million times by the five seconds it might take to fill in the form, he became depressed at the enormous number of person-hours that were essentially wasted on this task...
...Thus, reCAPTCHA was born. At this point you should be able to guess what it does: takes scanned images from actual books, with which optical character recognition software are struggling, and uses them as the source material for CAPTCHA’s...
Presumably they use a statistical model, since the "right answer" is not known at the start. The first people to decipher the CAPTCHA get a "bye", but as answers converge a "correct" answer emerges and serves as the standard. Once a 95% confidence interval is reached then the reCAPTCHA would be retired.
So even spammers, who will also attack these CAPTCHAs, will end up completing a social good. If they develop software that's exceptionally good at solving reCAPTCHAs, they can then sell their software to OCR companies.
Another example of a "good" side-effect of evil intent is that SSN cloning (persona cloning) can sometimes promote the credit record of the victim.
We all need to look for other opportunities to create side-effects of evil actions that have good effects.
Here's one. Create a myriad of sites that look interesting to hackers, but actually contain nothing of great value (ideally contain items that have deceptive value). Design the encryption key so that solving it helps with some social-good computation, such as protein modeling. Let well-funded hackers both waste resources and solve interesting problems.
The Centers for Disease Control, for example, receive 1-2 attacks per second from IP addresses based in China (AMIA conference, 2007). It would be nice to get something useful out of those efforts.