Want to look up information about a medical issue without thinking that someone might find out what you looked up? Do this.
You might be looking for a gift and don't want your partner to know that you've been looking at. This would ruin the surprise. Or maybe you want to look at YouTube without affecting what the site suggests the next time you visit.
Your beastie could be the private browser mode. When you search the web, all web browsers give you the choice to use a private mode. This includes Chrome's Incognito mode, Firefox, Safari, and Opera's Private Browsing, and Microsoft Edge's InPrivate.
And these secret browser settings will hide what you do on the Internet. If someone else operates your computer after you've done, he won't be able to view what sites you went to.
Using a computer in a hotel or library? A private browser lets you use a shared computer or someone else's device without saving your passwords, search history, or viewing information on that device. It also means that other people in the hotel or library won't be able to see what you looked up or watched online.
Trying to get into more than one email account? In private viewing mode, you can start a new tab and log in to more than one email account without having to log out of one account and log in to another.
Looking for gifts? You can buy things without telling anyone. Doing research on a sensitive subject? A secret website could keep you from being embarrassed or letting people know about a health problem.
Making trip arrangements? If you want to book cheap flights or hotels, a private browser may help because it stops web tracking. This makes it less likely that sellers will raise the prices of your tickets.