A lot of people know what incognito mode (or private mode) is at some basic level. They should use it when they want to do something "private" on the web. But I think most people don't actually understand what it means and how/why to use it. Perhaps this will help. Before we start - cookies are little bits of data used to track you between page loads. Think of it like a fingerprint. They're extremely important for session handling, so that a site can remember who you are from one page to the next. But they're also really handy for things like advertising services to track your activity on the web. When you open a new incognito window (and don't have one open already) - you're starting a new session in your web browser that doesn't have any of the cookies or caching that your "normal" browser window has. In practical terms, this means that when you visit a site, they won't have any history of you (mostly) and you may need to relogin, ...
A repository of handy little tips I'm building for the benefit of my fellow web developers.