Emails from Tesco, Asos, HSBC and more could be tracking your activity Menu Emails from Tesco, Asos, HSBC and more could be tracking your activity - what you need to know Emails from Tesco, Asos, HSBC and more could be tracking your activity - what you need to know. (Canva) Tracking technology is commonly used in emails by big compainies to track what you do on your device and create tailored content through emails. Some of the largest brands in the UK including Tesco, Asos and HSBC use email pixels to monitor a person’s activity on their device, this means your emails may be being watched and tracked for data.