Sold as a hosted service, Virtuity's BackStopp server monitors a protected laptop using any medium available, including the Internet, or locally using Wi-Fi or GSM.
If a laptop is reported stolen -- or even just moved from a designated space - the system can reach out and execute a file deletion routine that clears the laptop of all important data.
For laptops stolen while switched off, the location system can use RFID tags to make a judgement about whether that movement is within allowed parameters. A full log of all deletions is sent back to the service center once completed.
Ironic, or perhaps poetic justice that it's a U.K. company, considering the heavily publicized data losses last year in the U.K. Unfortunately, those were CDs, and this wouldn't help with that - unless someone comes up with a self-destructing CD.