The other day I was asked to help someone with a failing USB key someone had important data on. In Windows the key prompted the person to format the key, which they didn't want to do since they had lots of data on the key already. In Linux dmesg showed the correct size of the key, but didn't show any partitions. Under both operating systems the key appeared to be write protected so even if the end user wanted to format the key it wouldn't partition or format under either OS. In the end we managed to recover over 1,000 files stored on the key using foremost.
Read more at Charles McColm's blog.