Plug-ins are software programs that extend the capabilities of your browser in a specific way - giving you, for example, the ability to play audio or view movies from within Netscape Navigator or Microsoft Internet Explorer.  Think of them as third-party options. 

Not everyone needs Virtual Reality Modeling Language capability (VRML) — I sure don’t. And those who do probably have a preference about which of several dozen programs they want to use. I shouldn’t have to eat up 10 MB of disk space on a feature I don’t want, and the VRML fans shouldn’t have to hassle with uninstalling the rejected program for the preferred one. 

Plug-ins were developed by Netscape, and in theory, Netscape uses plug-ins while Internet Explorer uses Active-X controls to accomplish the same tasks. In reality, Netscape uses some Active-X and MSIE uses some plug-ins, but the was they work is pretty much the same. Plug-ins operate seamlessly with your browser. Typically, they make something happen in the browser window. You probably have some installed and don’t even know that they are there. In Netscape, go to help. . .about plug-ins, and you will get a list of the ones you have installed. Internet Explorer doesn’t have a similar list, or if it does I can’t find it. 

If you need a plug-in and it is not installed, you might get a warning window describing the plug-in, with a link to download it. You might get a "broken plug-in" icon, which may or may not have a link to get it. You might get a warning on the page that a particular plug-in is needed to make the page work correctly with a link to a download site. You might not get anything, which means you have to figure out what you need to make the web site run properly. Most plug-ins are free. 

Let’s look at an example. The Ricola site has an interactive herb garden that uses the Shockwave plug-in. This plug-in lets you scroll around a panoramic picture of a Swiss garden. Herbs are marked with a red box; when you click on one, another window pops up with a rotating picture and text description of the herb you picked. The site is at <www.ricola.com/herbgarden/index.html>. Look for the description of the required plug-in. If you think you have it, click on the text link at the bottom of the screen that says, "Directly to Herb Garden" and check it out. Newer browsers come with ShockWave pre-installed, so odds are you can view this. 

If you have to install a plug-in it can get complicated.  Some plug-ins and Active-X Controls will install themselves automatically, using a live-update procedure that takes little thought  or effort on your part. Most of these begin working immediately. Others must be downloaded onto your hard drive and then manually installed. (To do this, start. . .run. . .browse. . .select .exe file. . .OK. . . then follow the instructions.) Sometimes you will have to restart your browser, or sometimes even restart your computer. Some may give you a security alert (none of the ones I’ve listed do) so treat those with your own comfort level. Plug-ins are being upgraded constantly, so even if you have one installed it might not be recent enough to cope with the latest files. 

There are hundreds of plug-ins, and if you rush right out to download and install all of them you have defeated their purpose. Remember, they are options! Just get the ones you need, when you need them. Some plug-ins have limited use. If you are just curious, it might not be worth the time, trouble and disk space to download and install these one-time-use plug-ins. A few plug-ins are ubiquitous and are well worth the effort to install. Here are the five I recommend, but even with these, it’s probably not worth the effort to install them until you run into a site that uses them. 

Adobe Acrobat Reader:  
Get it from www. Adobe.com. This opens documents in a portable document format (pdf files) which is just what it sounds like. The creator of the document can use any software to create a document, convert it to a pdf file, and if you have the reader installed, you can open and print the page. The IRS uses this for income tax forms so it’s handy to have. If you want to try opening a PDF file to see whether you have the reader installed, go to <www.salsa.net/peace/mmm> and click on "download flier." 

Real Player: 
Get it from <www. real.com>. Audio and video, which is video and music that starts playing immediately instead of having to wait until the entire file is downloaded. The program litters icons all over your desktop, so if you have it, you’ll probably know it. Their web site can be confusing; make sure you get the free player and not the one that costs $29.95. To check if you have the capability of streaming media, go to the SAVAE web site and click on one of the sound samples. 

QuickTime: 
Get it at <www.apple.com/quicktime/download/index.html>. This is a movie player. Check out a sample at <http://www.salsa.net/peace/video/video.html>. The first public service announcement is in QuickTime format; the second is an MPEG video, which should open in your Windows media player. The third and fourth files are RealMedia files, which you’ve tested already. These files are really big, so set aside some time to let them download. 

Flash and ShockWave: 
Get both from <www.macromedia.com>. Flash delivers high-impact musical tracks, sound effects, animations and innovative interfaces. Shockwave Player allows you to view new forms of entertainment on the Web, such as games, music, rich-media chat, interactive product demos, and e-merchandising applications. There are lots of examples of both formats at this site that you can use as test files. 

Good lists of plug-ins are at <www.browserwatch.com> (click on Plug-in Plaza) and <www.netscape.com/plugins/index.html>.