You can break down the sites you visit into various categories including Procrastination, Communication, Search and Work. MeeTracker provides a baseline default setting for each of those categories so you don’t need to populate the categories yourself. If you want to, though, you can add groups and customize the default settings for the site groupings you want.
In addition to being able to accurately track time, you can also use MeeTracker to help you improve time usage. The deterrent feature can be set to flag you if you visit a site in a category that you shouldn’t (Procrastination for example).
MeeTracker does not have any data export features, which is a weakness. Overall though, MeeTracker (for Firefox users) is a simple, free and effective of way of tracking how you’re spending your browsing time.