One of the most widely misunderstood issues on the Internet is the difference between hits and unique visitors. The answer is that both these figures could in fact represent the same thing. If anyone who isn't a network engineer mentions 'hits' to you, they're probably trying to pull the cyberwool over your eyes.
Hits are the individual requests a server answers in order to render a single web page completely.
The page document itself plus the various images on the page and any other media files embedded there all represent individual requests to the web server. Each of these requests is called a hit - a hit is a request to the server for a file not a page. In other words, the more images used in a page, the higher the hit count - so while hits may be a good indication of poor page design, they won't tell you much about traffic. One individual request to view that page would count as 11 hits - one hit for the HTML code that makes up the page and 1 hit for each of the 10 images 'called' from the server. While a little more concrete than hits, page views do not give specific information about surfers or their behaviour, for example, the length of time that they remained on a specific page.