Proxy servers can store cached copies of sites. That is, when you access a particular location, you will get the data from the proxy. In all likelihood, it will load noticeably faster through the proxy. This happens because the load of a popular site you want to go to will suffer less if many people go to it through a gateway in the form of a proxy server. With such a server https://proxyverse.io you can monitor the traffic and "filter" it if necessary. It's like parental control. Only the scale is different. Such a proxy could be easily set up in a large company so that its employees could stay away from Twitter while they are busy running their business. Therefore, when logging into the social network, a warning might pop up with a request to get to work.