What does this website really do is open four different frames with Google Search in them, and for each one, you can get results for different things. You can close few frames to get better view of your search results. And even goog4 lets you change Google to some other search engine like wiki, blackle or bing.
This is particularly useful for people who have large screen monitors and want to search related terms at same time. Check 4xGoogle at http://googlegooglegooglegoogle.com/.