Answer:
Cookies
Step-by-step explanation:
Cookies are also known as HTTP cookies are known as unalterable data that is sent to and from the user browser or the website that the user is surfing.
These cookies, once set in place, work as private investigators, analyzing every move of the user without his/her knowledge. Vital information is sent unaltered and helps to give the user a satisfying experience.
For instance, a user visits an online phone retail company with the plan of buying 4 phones. The user discovers a phone to buy and adds to cart, after doing that, the user wants to keep searching for the other phones, the item added to cart will remain in the cart as the user keeps surfing for other phones. Cookies make that possible, if cookies were not in place, the cart would have reset back to zero once the user left that webpage.
In conclusion, cookies monitor the activities of users by sending information on their purchases and non-purchases, start, active and ending time.