Anonymous doesn't mean useless

Further to Charlie Clark's point (above), data can be gathered with personally-identifying information yet be effectively anonymised while retaining its value for statistical analysis.

My business recently conducted on behalf of a client a survey of 16,000 people at an event. Paper forms were distributed and a prize draw formed the inducement. To distribute the prizes, the form requested respondents' names, addresses and emails.

We received a surprisingly high response, mainly because our client is a trusted brand and had been very generous with the prize pot.

The form was designed so that the section containing the personally identifiable information could be readily cut off.

Thus we ended up with two piles of paper: the answers to the twenty-odd questions (which contained no personally identifiable information) and the names and addresses of the respondents.

The name-and-address portions were divided into those who had ticked the opt-in for email marketing and those who had opted out. The opt-outs were shredded: the opt-ins were added to an OpenOffice Calc (our client's preferred spreadsheet format) data file of email-shot recipients.

The statistical information was entered into an entirely separate MySQL database for analysis. It will provide a very rich source of information which will allow our client to improve the event and target its market spend more cost-effectively in future.

A good result for us and our client - and one achieved without anyone's privacy or identity being compromised.

All this - and no boffins involved.