Sandboxie runs your programs in an isolated space which prevents them from making permanent changes to other programs and data in your computer.
-The program is shareware not freeware. (Through a generous shareware)
-Secure Web Browsing: Running your Web browser under the protection of Sandboxie means that all malicious software downloaded by the browser is trapped in the sandbox and can be discarded trivially.
-Enhanced Privacy: Browsing history, cookies, and cached temporary files collected while Web browsing stay in the sandbox and don’t leak into Windows.
-Secure E-mail: Viruses and other malicious software that might be hiding in your email can’t break out of the sandbox and can’t infect your real system.
-Windows Stays Lean: Prevent wear-and-tear in Windows by installing software into an isolated sandbox.
P.S This is not just useful to surf porn sites.. btw keep always antivirus running as well