Storage space is set to increase as worldwide e-mail traffic is expected to reach 35 billion a day by 2005. E-mails now account for up to 40% of the cost of storing data in many companies’ computers – and many IT directors fear that more than 20% are personal e-mails circulated by staff. The pressure on storage systems will be compounded by the possibility of European regulations following in the wake of the North American Sarbanes Oxley Act of 2002, which makes specific provisions for the retention of documents relating to the audit process for a period of years. Despite this, a survey of IT directors conducted by Hitachi Data Systems finds that most companies are failing to address the problem of archiving growing volumes of e-mail data.