Web hosting is a service that provides a physical location in which a web site resides. Customers' websites are stored on computer servers located in secure and climate-controlled environments and permanently connected to the Internet through high-speed data lines. Customers can work on local webpage files and then upload them to the server. As soon as the pages are uploaded to the server, they become live visible to anyone surfing the World Wide Web. Web hosting providers usually charge a monthly fee for hosting services. Some providers host websites free of charge. In these cases, the services are usually paid for by the placement of small ads on the sites being hosted.