This program is, as its name clearly suggests, an application that helps you prevent other users from accessing certain webpages from your Mac. You might find this utility to be of good use if you wish to block your children from browsing websites containing adult content.
Website Blocker brings a straightforward interface and simple to configure security settings. All you need to do to block webpages is to enter keywords from the website title or paste its URL address, click the Apply button, and activate the app's protection feature.
In my testing, I tried accessing the BBC homepage from both Mozilla Firefox and Safari browsers after I completed the aforementioned steps (enter BBC as the keyword and www.bbc.com as the URL address). Once I attempted to access BBC webpage with Safari, the tab immediately closed. Unfortunately, this wasn't the case with Firefox (only "Block websites by title" option works - blocking by URLs is not currently possible with Firefox).
Another aspect I don't like about this utility is that it offers a small amount of webpage blocking settings. For instance, the app lacks an option to block websites at a certain time of the day, or for a pre-defined period of time.
Nevertheless, the application is free of charge. Hence, it's up to you to decide whether it's worth installing and using this app on your Mac for blocking webpages.