According to Wikipedia, a website (or "web site") is a collection of related web pages, images, videos or other digital assets that reside on server computer at a web hosting company (or sometimes in-house), usually accessible via the Internet. All publicly accessible websites are seen collectively as constituting the "World Wide Web."
The internet itself is a conglomeration of websites amongst other pieces of information. Users will create websites to do one of a few things: provide news and / or information, provide a search directory, sell products, provide an interactive experience between users, or a combination of the above.
Bloggers may write about websites when they're they're discussing others websites or their own, doing a review on a website, providing information on how to design or program a website better, or even improve the search engine optimization or lookups. Other reasons even include reasons to purchase a website, or the discussing the latest gossip website.