Little Snitch was created to help you protect your privacy while working with Mac tools having access to the Internet. To be more exact, the utility will notify when one of your programs attempts to connect to a server on the Internet and you will be able to allow or deny the connection.
The tool is user-friendly and offers various helpful tips. It provides you with a detailed traffic history report for the last hour (helpful if you need to learn which programs are connected to the Internet), a map representation showing the location of the servers you were connected to, and accurate statistics based on your Internet traffic data. Another great thing is that you can easily configure the rules settings for each of your Mac apps.
There are two inessential aspects that can bother you a little: you need to restart your Mac after installing Little Snitch, and it might take a while to launch the utility. Other than that, I have nothing bad to say about this tool. It does exactly what's been said on the homepage of the developer and provides you with a wide variety of helpful features. Plus, it comes with a very reasonable price.