A VPN is a kind of service that secures your data. It renders your ISP unnoticeable. Sometime, ISPs block online services and websites. It's for security purposes. This problem is widespread in countries that have severe censorship regulations are implemented. This can be prevented by a VPN. For instance, http://raymondfcunf.loginblogin.com/15184257/examine-this-report-on-what-is-a-vpn