Google is one of the most used search engine in the world. A basic search engine what it does is sift through the internet for relevant webpages depending upon the keyword you submit. In 1990's search engines were really slow, coming up with useless webpages etc. It is around that time ,two computer graduates larry page and sergey brin met at stanford. Both of these graduates dreamed about creating a search engine which would yield faster web results
Together in 1996,they decided to build a better search engine. They realised that webpages should be categorised depending upon the popularity and depending upon the number of weblinks it has.They wrote a algorithm called blackrub, which meant it can do back link analysis. They started building server networks cheap and borrowed pc's. They used their own credit cards and also borrowed money from their friends and families. Then finally they started their own company with a capital of $100,000. Google got its name from a mathematics word GOOGOL, which means a very high number 1, followed by large number of zeroes. They tried to license the technology, but nobody was willing to buy it at such an early stage,therefore they kept google to themselves,acquired more capital and improved the product
The $100,000 dollar cheque was given by the co founder of sun microsystems, after a quick demo of the software. Google.in company was formed and a beta version of google was opened. In a day it answered around 10,000 queries. In 1999, the beta version was finally removed
HOW GOOGLE WORKS?
Now basically when you enter a keyword in google,what exactly happens. Suppose if you want to search for a particular chapter in a book,what do you do first?check the index isnt it? Now how is the book so organised? It may have referred many sources and formed a combination of all the results
Similiarly google works on the principle of parallel network processing. It consists of a distributed network,which has many computers linked to it. Because of parallel processing,data is acquired at a faster rate. Google has 3 main parts
- Googlebot
- Index
- Query processor
Now lets see what all these does in detail
GOOGLEBOT
Googlebot is like a spider, which crawls and fetches information and the specific webpages when you enter the keywords.Basically what it does is that it finds and retrieves the pages containing your keywords and hands it over to the indexer. Its function is basically similiar to a web browser, when a keyword is entered, it requests for a webpage from the webserver, downloads the whole page and then sends it to the indexer
Googlebot mainly consists of a large number of computer which is capable of requesting and downloading pages at a much faster rate. When it requests a page, it organises all the links in that webpage for further crawling. By organising all these links in every webpage,it may be able to access every single page on the web. Ofcourse this may take some time, therefore the page might be crawled once in a month
Even though its function is very simple,googlebot has to take care of many things. First it should ensure that it does not fetch the same webpage which is already there in the index. This is because a large amount of resources are utilised in searching for a webpage and since it sends simultaneous requests at a time, there is a possibilty that it may crawl the same webpage again. Also it should determine how often it should revisit a page
Also it should keep the the index current,that is some webpages constantly change their contents,like stock exchange,newspapers articles etc. If this is not re-indexed, what will happen is that when user requests this page, google will present with its old data.Therefore it re-visits certain pages, depending upon how fast these pages changes its contents
INDEXER
Indexer is similiar to the index page of our book. Whatever page,googlebot downloads, the entire text is given to the indexer and it is stored in the database. When a keyword is entered,index is stored alphabetically and each index entry will contain the documents where this keyword occured. Because of this sorting algorithm,it is easier to access the documents at a faster rate.
In order to improve the performance of google,what it does is that it ignores the words like 'the,is,or are ' etc. This is done to narrow down the search results, as these words have no impact on the search results.. Also it removes punctuations,multiple spaces and convert all the letters to lower cases to improve the efficiency
QUERY PROCESSOR
Query processor basically contains the search box and it formats the queries and matches them to the resultant documents.Google ranks webpages depending upon its popularity and how often the keywords appear in the webpages and also where it is present in the page. If it is present at the top of the page,then it is given a higher rank. If you are posting a query, then it also checks how close the subsequent words appear in the webpage. It gives more preference that have search page near each other and also in the same order as the query.
So basically once a query is entered, the googlebot sends a message to the webserver requests the page and downloads them, then it is send to the index servers. Index servers tells which page the word occurs. Then it is send to the doc servers and it accessses the required documents. snippets are generated to describe each search result and the searches are then returned to the user in a fraction of second.
HOW DOES GOOGLE MAKE MONEY?
Basically everything you use in google is for free,so how does it gain money.The answer is simple, it gains money through advertisements.
ADVERTISEMENTS
when you search on google,there is a section called sponsored links based on the search you have give. When you click these ads and visit these websites google charges a certain amount of money to the website for the link. This is called google adsense and it is the main source of income for google. Now how much google charges for a click? It depends upon what kind of advertisement you want to put up. When you want to advertise somethin, you will have to select some keywords.. This is where google plays their ace card.. They have a sort of bidding system for the keywords.. So the price you pay, will depend upon how many companies are bidding for that keyword.. If there are more companies bidding for it, then you will have to pay more.. So a keyword like finance, health will result in a considerable amount of money and companies who wishes to advertise with these keywords will have to pay a lot of money per click.. so imagine how much google can earn?
They do not sell anything, all they sell is traffic. Basically it gets paid for selling traffic to the websites which places ad in google.. That is why they have to increase their reach, they have to show their potential so that more and more companies will put up advertisement in google.. If the traffic or number of people using google is very high, then theres a fairly high chance of increasing the traffic to the websites which put up their advertisments.