To abide by the ruling, ISPs are obliged to delete whatever information they garner from their customers, including ISP addresses, which would allow the ISP to track whatever web sites a customer visits.
T-Online customer Holger Voss argued that his service provider had overstepped the mark by storing data above and beyond that which it needed for invoicing purposes. The court agreed with him.
It seems that T-Online could face a fine of 100,000 Euros or face the prospect of having the board of directors banged up for six months if it fails to comply with the ruling.
In Germany, ISPs are also obliged to hand over whatever data they may have on customers to the customer, on request.
German site Heise has a long, complicated case report here in German. ยต
* APOLOGIES, we inadvertently published the wrong name in the earlier version of this story.