Website Dimensions
Website dimensions can be measured in different ways. But the most common method is by counting the number of unique visitors it gets. The following list is based on the number of unique visitors a site receives.
The Top Ten Most Visited Sites
Google sites are at number one with 844 million distinctive visitors monthly. It is followed by Microsoft sites with a total of 691 million unique visitors. At number three are Yahoo! sites with 581 million.
Facebook is at number four with 340 million. The fifth spot belongs to the Wikimedia Foundation with 303 million visitors. These sites include Wikipedia and the other related sites.
At the sixth spot is AOL with 280 million unique visitors. The online auction eBay is next with 233 million. The eighth spot is held by CBS Interactive with 186 million visitors. The online retail store Amazon is number nine with 183 million visitors. Rounding off the top ten is the Ask Network with 174 million.
This list is worldwide. In the US, the number one site is Google. It is followed by Yahoo!, Microsoft, AOL and Fox Interactive Media.
It should be stressed that these figures are estimates only. 
Of all the sites mentioned above, Facebook is the fastest growing. One more thing needs to be said. Facebook only counts registered visitors. While it has millions of registered users, many millions more visit the site without signing on.
Other Ways Website Dimensions Can be Determined
The number of visitors is just one way to measure a site. The number of pages on the site is another way. There are no official records being kept for this.
However, there are some obvious contenders. The list would include eBay, Amazon, Facebook, Google, Wikipedia and Yahoo!. If one counts each Gmail or Yahoo! site separately, the total will run into the millions.
Number of Web Sites and Pages
This is difficult to determine. In 2007, the Netcraft Web Server Survey showed there were 108,810,358 websites. That same year, Netcraft also tried to estimate the number of web pages around. Their estimate was 19.2 billion pages. The average number of pages per website was 273. Needless to say, these are ballpark figures only.
The website dimensions described here undoubtedly changed. Because the World Wide Web has no central server, it will become very hard to get the right figures. Since the very nature of the web is dynamic, it is hard to see how this can change.
