Plotline: a laptop is stolen from this Minnesota software programmer's wife. This guy had previously installed SETI@Home in his wife's laptop. Using the logs on SETI@Home servers, this guy was able to detect where the thief was located, thus alerting the police, which in turn capture the thief and recovered the stolen laptop.
Now for the details:
SETI@Home uses volunteers' computers when they go into screen-saver mode to crunch data from the Arecibo radio observatory in Puerto Rico in an attempt to try and spot signals in the radio noise from space, hoping it comes from little green men.
James Melin, a software programmer in Minnesota, runs SETI@home on his seven home computers, which periodically check in with University of California servers. Whenever that happens, the servers record the remote computer's Internet Protocol address and file it in a database that people running the SETI software can view. One of those seven computers on which Melin installed SETI@home was his wife's laptop, which was stolen from the couple's Minneapolis home Jan. 1.
In an attempt to recover the stolen laptop, Melin monitored the SETI@home database to see if the stolen laptop would "talk" to the Berkeley servers. Indeed, the laptop checked in three times within a week, and Melin sent the IP addresses to the Minneapolis Police Department. The police was then able to determine the real-world address where the stolen laptop was logging on and within days, they seized the computer and returned it to the rightful owners.
While no pertinent documents were deleted or tampered with, Mrs. Melin noted that the perpetrator (or the eventual underground buyer's) taste in music was among the worst she's ever heard of judging by the foreign tracks that were gifted to her when the laptop returned.
Source: News Journal Online, Engadget