firefox configuration

[Josef Lowder]

When I go to certain websites, Firefox puts the following message 
at the top of the Firefox window: 

"Additional plugins are required to display all the media on this page." 
with a button on the right side that says: "Install Missing Plugins" 

How can I get rid of this message? 

I have been of the opinion that I do not want to install any plugins, 
especially Macromedia flash as it has been my understanding that 
this is something to avoid.  Is that a misguided opinion?  Seems to 
me that most of this "fancy" stuff is a nuisance.