Microsoft silverlight

Hi
i like to ask what is the purpose of microsoft silverlight.
Cause it has been in my computer for a long time, and i don't know what is it for?

Hello,

Silverlight is a web application framework that provides functionalities similar to Adobe's flash. It's sometimes required to run certain Microsoft website functions.

In the case of the average web user, you'll know you're visiting a page that uses it if you see a loading animation comprised of swirling circle of blue dots with a completion percentage in the middle. It still has nowhere near the reach of Flash, so you don't see it being used in the majority of websites today. MSNBC.com uses it to deliver some of their streaming media.