The frustration that many Internet users experience is often due to some common misunderstandings. Following are a few things that might be sabotaging your searches:

• Great Expectations. Whereas it is true the Internet is a wonderful tool
for researchers, like anything, it has its limitations. I would never suggest an individual do all her research seated at the computer; we simply are not at the point where the information on computers can replace that found in traditional library research.

Consider that one of the world's leading research institutes, Russia's Moscow State University, holds some eight million items in its library. Yet so far, less than 200,000 of those items have made their way onto the Web ( www.msu.ru ).

And even when documents get posted online, it may be weeks or months before a site is picked up by a search engine's database.

Other documents remain part of the hidden Web, beyond the grasp of most
search engines.

1 Certain material, such as proprietary corporate information, may never be accessible online.

2 A recent study showed that despite the best efforts, search engines reach only a small percentage of sites on the Web.

In other words, believing you can find everything and anything online is unrealistic.

Source:
Book Title: Web Search Savvy: Strategies and Shortcuts for Online Research. Contributors: Barbara G. Friedman - author. Publisher: Lawrence Erlbaum Associates. Place of Publication: Mahwah, NJ. Publication Year: 2005. Page Number: 20.