File-sharing systems, such as Kazaa, make it relatively easy to trace who is hosting which files by linking them to specific net addresses.

BBC: NEWS | Technology | Microsoft targets source pirates

Allianz, for example, which settled most of its policies under Germany's own sweeping post-war restitution programme, set up a team to examine 1.4m individual paper files on policies issued between 1920 and 1945 in order to try to trace any that remain unpaid.

ECONOMIST: Holocaust reparations