Increasingly, users are opting for mobile proxies to work online and maintain multi-accounts. Such services allow for automated activities without the risk of being blocked. This type of proxy is ideal for parsing, traffic management and many other tasks.
Depends on where you are. If you are trying to unblock sites from school I suggest not doing so, especially if you have a good tech. If you are trying to access blocked sites from home you need to use either a proxy site or disable whatever blocking system is being used.