We sold web traffic analysis software to Dell Europe, around 1998 or so. They never kept their data more than a week. As the traffic and purchase behaviour they were analysing in the store changed so much every week they said (if I remember correctly) it didn’t make any sense to compare the data over time. I took from that that what they sold every week changed all the time. Of course, data storage and processing was then not as cheap as it is today, so maybe there was more to it.