How to create a fake identity and stay anonymous online

You don't need to have evil motives for wanting to fake your identity or go incognito online; for many people, it's a matter of privacy and avoiding spammers and scammers. Thankfully, there are a great many tools for staying anonymous online. Here are a few of the best.
The browser's incognito mode
The private browsing mode in Google Chrome, Firefox and other browsers records no information about your browsing, including form data you enter, files you download or history of pages you visit. It's handy for many things beyond porn. To launch a window in private browsing mode, use these keyboard shortcuts:
Chrome and Opera: Ctrl+Shift+N
Firefox, Internet Explorer: Ctrl+Shift+P
For Safari, go to Safari > Private Browsing.