What is plugin? why it is a matter of talk?

Answer 1

is a software component that adds a specific feature to an existing computer program. When a program supports plug-ins, it enables customization. for instance, browsers like firefox have many plug- ins, such as youtube downloader, yahoo tool bar, etc in simple words is a web application(extension) that you have the option to add!
I hope it helps!

Answer 2

plug ins are small software modules that help in making the usage of a S/W more reliable and user friendly