Shopping online

Leaving comments on social media 

Simply clicking “OK” anywhere on the web

Through Mobile Phones, Tablets, or Laptops.

Making a Skype call, sharing something on Facebook, uploading pictures to …, sending an email to a Hotmail user. For instance, if you Tweet that you have just arrived in Sydney and the sunset is spectacular, those are quite explicit disclosures about where you are and when (assuming you're telling the truth). Each time you visit a web site, you reveal some information about yourself to the owner of the web site: your IP address, which may include your geographic location, your web browser type and operating system, and, often, the last web site you visited. 
BIG:
Internet services such as online commerce, social networking, and web mail require that a web site be able to link up multiple interactions, such as putting a book in a shopping cart, and later clicking “Pay Now”. They need to know when the person doing something now is the same person who did something previously – and often this is in the user's direct interest, too.