Because of this, they often contain a lot of irrelevant information and it can be difficult to wade through the rubbish to find the quality pages.
Search engines are far more comprehensive than subject directories.
The size of search engines can be huge and the number of sites indexed by search engines can contain hundreds of millions of pages. Because search engines all work a little differently it is important to understand the search syntax for each search engine. I have created a Comparing Search Engine Capabilities comparison chart which is a quick reference guide to help you with effective Web searching. This briefly provides you with the syntax used in the different search engines. The following lists all the multidisciplinary freely accessible search engines which claim to collect sites worldwide.