In many cases the new file types are supported by modern browsers, but there are still numerous formats that require special viewers. The Web often serves as a pipeline from a server to a viewer application. The actual differences between plug-ins and helper applications are few, but worth noting. When a plug-in is required to view data, it often uses the same display area as the browser itself. Also, plug-ins are usually browser specific, meaning they can only be installed into a specific vendor's browser and often a specific version of that browser.
Helper application are usually stand-alone applications in their own right.
Browsers hand off data streams to helper applications then get out of the way, since helpers have their own display areas. Helper applications are not browser specific. If a viewer is required by a file format, and that format type is not already defined in the MIME table of the browser, the user will be prompted to choose between locating a viewer, saving the file, or terminating the transfer. You may take this into consideration when making a selection between multimedia formats to include in your own Web site. Another aspect of good multimedia stewardship is the determination of whether to mandate or offer viewing of the media thrill.