Web Technologies 4: Search Engine Indexing & Page Rank Algorithm
Search engines help find info on Internet
A search engine searches its database(Index)
Info gets onto the index via web-crawlers / spiders (bots)
They follow links on pages & send back data URL / content details:
-how many times different words appear on page
-last update
-headings in <h1> tags
-words in <title>
-URL
database (index) searched for relevant words in search terms.
Page Ranking Algorithm
Help users find relevant info quickly
Includes - number of times word appear & external sites pointing to pages (links)
The importance of the Page rank of a page goes up the more links point to it
However, the value of the linking page is diluted the more outbound links there are
(formula to work this out includes dampening factor(d))
Algorithm constantly tweaked to guard against abuse.
Search engines help find info on Internet
A search engine searches its database(Index)
Info gets onto the index via web-crawlers / spiders (bots)
They follow links on pages & send back data URL / content details:
-how many times different words appear on page
-last update
-headings in <h1> tags
-words in <title>
-URL
database (index) searched for relevant words in search terms.
Page Ranking Algorithm
Help users find relevant info quickly
Includes - number of times word appear & external sites pointing to pages (links)
The importance of the Page rank of a page goes up the more links point to it
However, the value of the linking page is diluted the more outbound links there are
(formula to work this out includes dampening factor(d))
Algorithm constantly tweaked to guard against abuse.
