Andrew reviews the latest web searching innovations in six areas: Popularity engines, better meta search, meaning-based search, natural language interfaces, expert search and pay-per-click search engines. Read below to find a summary of each story and a link to the full text.

1. Popularity Engines
Search results are ranked according to a formula which supposedly measures how many users click on a certain site for a given search term. Examples are Direct Hit, Alexa, Yep.com and Google.

2. Meta Search Engines
Meta search engines are tools that check all search engines and return a listing of the web pages that scored highest based on an aggregate keyword relevance score. Examples are Metacrawler, Mamma.com and Ixquick

3. Meaning-Based Search Engines
Meaning-based engine have developed proprietary lexicons that allow users to zero in on particular meanings for a given keyword or scan the text of a document and analyze the relationships among words to help in placing documents in specific categories that describe what they are about overall. Examples are Oingo, SimpliFind and ejemoni.

4. Natural-Language Search Engines
Performs searching by phrasing web searches in the form of a question Examples include Ask Jeeves Read the story > Move Over Exclamation Point, Here Comes Question Mark

5. Expert Guide Sites
Expert sites manned by either paid or volunteer guides help users find answers to any question or problem imaginable, in real time. Examples include About.com, ExpertCentral, AllExperts, EXP and AskMe

6. Pay-Per-Click Search Engines
PPC engines enable sites to buy their search rankings under any keyword combination. Examples include GoTo.com, Searchound, FindWhat and Kanoodle.