Reddit History records your Reddit browsing history and that's about it. If you click a link whilst on reddit then the link will be added to your Reddit History. You can navigate through the simple UI to find previous links you clicked when you forgot the name of that... po.. litical figure doing something.
In the event that you don't want to remember how often you visit /r/ConvinceMeIAmAGoat, click the clear history button and no one will ever know how weird you are. You EVEN have the option to remove specific links in case you don't want to lose all your precious data from /r/EnlightenedBirdMen.