In fact, the web is also home to many other kinds of documents — slide shows, financial tables and other documents.And there is a little-known feature of Google Advanced that allows you to find these treasures. (You’ll find Google Advanced by clicking on the “Advanced Search” link on the main Google page or by going to www.google.com/advanced_search.html )

The third line in the Google Advanced box is called File Format.By clicking on the small arrow on the right hand side, you can tell Google to narrow your search not just to web pages, but other formats such as .ppt, .pdf, .doc and .xls files. You should never do only a format search.

Obviously, good information about many subjects can be found on normal web pages and you should always do a general search for your topic as well. But by selecting certain specialized format searches,Google is helping you hunt through the invisible web — the millions of documents and slide shows and appendages that do not appear at first glance on web pages.

Let’s take a look at each of these formats.

PPT files are PowerPoint slide shows.Many companies, governments and organizations put slide shows on the web for their members or the public.You can find these shows and display the images,graphics and information on your own computer. For example, if you wanted to see if the American military had produced a slide show on the anthrax vaccine: - go to Google Advanced and put in anthrax as your keyword - under Format, select .ppt - under Domain, type in .mil (This restricts the search to the military sites of the US Armed Forces. For more on Searching by Domain, see the JournalismNet column in Media magazine Fall 1999, vol.6- www.journalismnet.com/tips/domain.htm)

If you click on any of the results, you can watch the slide show — complete with graphics — and save it on your computer— providing,of course,you have PowerPoint installed. If you don’t have PowerPoint installed on your machine,you can at least see the text and images of the slide show in a web page format.You can do this by clicking on the words “VIEW AS HTML” right next to the results. You won’t get the effect of the show but you will get the content.

SPREADSHEETS

If you are looking for statistics, growth rates, comparisons — anything that is likely to be best written or presented in a table — then you can assume someone has written it and stored it on the web in an Excel format. For example, let’s say you want to examine gasoline and cigarette taxes by province in Canada: - go to Google Advanced and put in as your keywords cigarette taxes world - under Format, select .xls

When you click on the result,your Excel program launches and gives you the table.(Again, if you don’t have Excel installed on your machine, you can at least see the text in a web page format by clicking on the words “VIEW AS HTML”right next to the results.You won’t get the complete effect of the table but it is usually quite comprehensible.) Tables do not have to be strictly financial or economic. People use Excel to track any kind of historical or statistical trend.

Here is another example.Research on the global arms trade should be done using the usual general search techniques. But go to Google Advanced and perform an .XLS format search like this: - put in as your keywords global arms trade - under Format, select .xls

The third format we’ll look at are .pdf Acrobat reader documents. When companies or governments want to put out official documents and preserve the look of those documents, they produce documents in the .PDF format. PDF stands for portable document format and it allows you the reader to see the document in exactly the same format — with all the illustrations,boxes, forms and page breaks — as the person who created it.> For example,many government tax departments produce PDF files on the web to make sure everyone fills out the same form. Many application forms, manuals and official reports exist on the web in .PDF format. (You must have Adobe Acrobat Reader to retrieve .pdf documents.Adobe’s reader is free and can be downloaded at www.adobe.com.)

Let’s say you were investigating the controversy over the use of depleted uranium in Kosovo.Go to Google Advanced and make the following request: - put in as your keywords “depleted uranium kosovo.” -under Format, select .pdf You’ll get several results, including a 74-page report from a UN mission.

Many people also use Microsoft Word to write reports, essays, studies and pretty much everything else they type on their computers except for email.The documents are stored on your computer as .DOC files. Some web sites will then simply import their members’writings or reports as .doc files.This is not as useful a search as the other formats,but it can still turn up some gems.

Universities in particular post a lot of .doc files on their web sites since so many professors and students do their work in Word and it is easier to share information that way. Armed with this knowledge,you can do some sophisticated searching.Let’s say you need research on the Russian election of 1999 that brought Vladimir Putin to power. You assume Harvard University has done some work on this. Go to Google Advanced: - put in as your keywords russia election 1999 - under Format, select .doc - under Domain, type in .harvard.edu

(This restricts the search to the Harvard web site. You will get several research papers on the topic.If you click on the links,you will open up a Microsoft Word document. To sum up,we have seen how to search for official reports and documents (.pdf and .doc files),tables and spreadsheets (.xls files) and slide shows (.ppt files).

But be careful — you should always combine these restricted searches with a general search for all kinds of web pages to make sure you don’t miss some valuable sites.