By combining its existing 1m names (gathered from people who had responded to previous offers on tinned goods) with lists of similar households bought from brokers, Heinz has built up a database of 4.6m people to send a copy of At Home, a free magazine of recipes which also promotes its products.

ECONOMIST: Hi ho, hi ho, down the data mine we go

Among the first to go were Metromail, a direct-mail-database company, and Donnelley Enterprise Solutions, which ran copy departments and mail rooms for law firms and the like.

FORBES: Magazine Article

When one of the registrars sends an addition, deletion or modification to a DNS record, SnapNames receives a copy of that change and maintains its own comprehensive database of domain name registrations called Whois.

CNN: New service back-orders domain names

The opposition Conservatives say that if they win power at the approaching general election they will copy the Scottish system, in which people who are not convicted usually have their DNA removed from the database as soon as the case against them is dropped.

ECONOMIST: The vast police directory is trimmed, but only a little