A website (also written as a web site) is a collection of web pages and related content that is identified by a common domain name and published on at least one web server. Websites are typically dedicated to a particular topic or purpose, such as news, education, commerce, entertainment, or social media. Hyperlinking between web pages guides the navigation of the site, which often starts with a home page. The most-visited sites are Google, YouTube, and Facebook. All publicly-accessible websites collectively constitute the World Wide Web. There are also private websites that can only be accessed on a private network, such as a company's internal website for its employees. Users can access websites on a range of devices, including desktops, laptops, tablets, and smartphones. The app used on these devices is called a web browser. Multimedia and interactive content Early websites had only text, and soon after, images. Web browser plug-ins were then used to add audio, video, and interactivity (such as for a rich Web application that mirrors the complexity of a desktop application like a word processor). Examples of such plug-ins are Microsoft Silverlight, Adobe Flash Player, Adobe Shockwave Player, and Java SE. HTML 5 includes provisions for audio and video without plugins. JavaScript is also built into most modern web browsers, and allows for website creators to send code to the web browser that instructs it how to interactively modify page content and communicate with the web server if needed. The browser's internal representation of the content is known as the Document Object Model (DOM). WebGL (Web Graphics Library) is a modern JavaScript API for rendering interactive 3D graphics without the use of plug-ins. It allows interactive content such as 3D animations, visualizations and video explainers to presented users in the most intuitive way.[10] A 2010-era trend in websites called "responsive design" has given the best viewing experience as it provides a device-based layout for users. These websites change their layout according to the device or mobile platform, thus giving a rich user experience.[11] Types Main article: List of types of websites Websites can be divided into two broad categories—static and interactive. Interactive sites are part of the Web 2.0 community of sites and allow for interactivity between the site owner and site visitors or users. Static sites serve or capture information but do not allow engagement with the audience or users directly. Some websites are informational or produced by enthusiasts or for personal use or entertainment. Many websites do aim to make money using one or more business models, including: Posting interesting content and selling contextual advertising either through direct sales or through an advertising network. E-commerce: products or services are purchased directly through the website Advertising products or services available at a brick-and-mortar business Freemium: basic content is available for free, but premium content requires a payment (e.g., WordPress website, it is an open-source platform to build a blog or website). Some websites require user registration or subscription to access the content. Examples of subscription websites include many business sites, news websites, academic journal websites, gaming websites, file-sharing websites, message boards, Web-based email, social networking websites, websites providing real-time stock market data, as well as sites providing various other services.