A Money Mail investigation found dozens of major High Street retailers now harvest customers' email addresses - including Debenhams, Mothercare, Argos, Halfords, Topshop, Dorothy Perkins, New Look, Next, Selfridges, Wickes and Joules. Typically, shop assistants tell customers this is to email them a so-called 'e-receipt', rather than printing one at the till.

In the military, a poorly formatted email may be the difference between mission accomplished and mission failure. During my active duty service, I learned how to structure emails to maximize a mission's chances for success. Since returning from duty, I have applied these lessons to emails that I write for my corporate job, and my missives have consequently become crisper and cleaner.

Identifying customers in-store is a vital way of building up a complete profile of their spending patterns and multichannel shopping habits. This can then guide display advertising, CRM initiatives, Web personalisation and overall buying strategy. The challenge is in getting the proposition, process and use of the data spot on.

An e-receipt can be more convenient at times, but it is also a way for shops to collect personal data about their customers and send them marketing. In the run-up to the busy Christmas season, the ICO is reminding retailers that people have the right to know what happens to their personal data. Retailers need to be aware of the obligations under data protection and privacy laws.

Ireland's Data Protection Commissioner (DPC) said on Monday it was trying to ascertain whether Yahoo's decision to scan clients' email accounts at the behest of the U.S. authorities last year broke European law. Sources have told Reuters that Yahoo used a software program to sift through millions of emails for specific information related to national security.

Every day, Ocado’s customer contact centre in Hatfield, Hertfordshire receives some 2,000 emails from customers. Some customers email to say they are delighted with their online grocery orders. Some, inevitably, are disappointed or downright disgruntled. If bad weather or major traffic incidents lead to delivery delays, the number of daily emails can rise to as much as 6,000. 

According to Grammarly -- an online proofreading tool -- the most opportune time to answer emails is between the hours of 1 pm and 5 pm. The study looked at data on words that needed to be corrected and at what time, and found that emails written from 1-5 pm contained only 3.7 errors per 100 words.

Breaking up your email lists into different categories and tailoring your writing to each audience might seem like more work, but it's really not. But according to email marketing service MailChimp, segmenting lists has an overwhelmingly positive impact on click rates and engagement. It found that targeting emails by interest group increased clicks by 64.61%.

Until recently, email marketing was never able to send a separate email specifically to mobile devices because that web technology relied on javascript user agent sniffers. Responsive web pages offered great user experience for desktop and mobile. Email followed this trend a few years later. Email could now be coded to work or display differently on mobile devices for a better user experience.

"GDPR brings a more 21st century approach -- the right of consumers to data portability is new, as is mandatory data breach reporting, higher standards of consent, and significantly larger fines for when companies get things wrong. But the big change is about giving consumers control over their data. I believe this is a positive development."