According to an official Google blog post, the Google sites Service released several months ago for enterprises and organizations has been open to all users, however, you may need a Google Apps account. Even if you do not have your own domain name, you can use http://sites.google.com/#your-website] to create a website. You can add any number of pages for free.
Unlike Google's existing Google pages, Google sites meets more collaborative needs. you can create your own team portal to share information, while Google pages prefers to create traditional websites, google pages allows you to use your own domain name and better control the appearance of your website.
On the contrary, Google sites gives you more collaborative functions, which do not have much visual control. Google sites can be seen as a wiki site. You and your colleagues, you can easily publish or update content here.
Source: http://blogs.zdnet.com/Google? P = 1051
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