Introduction – What Is SEO

SEO is a technique which helps search engines find and rank your site higher than the millions of other sites in response to a search query. SEO thus helps you get traffic from search engines.

search engines perform several activities in order to deliver search results – crawling, indexing, processing, calculating relevancy, and retrieving.

This task is performed by a piece of software, called a crawler or a spider (or Googlebot, as is the case with Google). Crawlers are not humans and they do not see images, Flash movies, JavaScript, frames, password-protected pages and directories.

If the website have more traffic then search engine will crawl it in very short times in comparison with other websites.

The indexed page is stored in a giant database, from where it can later be retrieved.

When a search request comes, the search engine processes it – i.e. it compares the search string in the search request with the indexed pages in the database. Since it is likely that more than one page (practically it is millions of pages) contains the search string, the search engine starts calculating the relevancy of each of the pages in its index with the search string.

There are various algorithms to calculate relevancy:- keyword density, links, or metatags.

Each of these algorithms has different relative weights for common factors. That is why different search engines give different search results pages for the same search string.

Why we use SEO :- Ranking, backlink, traffic, popularity, PR
Why Client requird SEO :- Return on investment (ROI)
Benefit of SEO :- ROI, Long term position, target traffic, ranking on different search engine.
Why client required ranking on different search engines :- They have different database, different user, and country wise their popularity.
But why we use google :- Because it provide PR ;)

Two types of SEO and their Percentage :-
On page :- 30%
Off page :- 70%

Algorithmic Results

Algorithmic results are the ranked listings search engines provide in response to a Query. They are often referred to as Organic Listings in contrast to Paid Listings because their rank is based on relevancy rather than advertising revenue paid to the search engine. However, paid listings do appear alongside algorithmic results in many search engines, provided they are relevant. Improving a website's unpaid algorithmic results is known as Natural Search Engine Optimization.

Crawler

Also known as Spider or Robot, a crawler is a search engine program that "crawls" the web, collecting data, following links, making copies of new and updated sites, and storing URLs in the search engine's Index. This allows search engines to provide faster and more up-to-date listings.

Organic Listings (or Organic Optimization)

Also known as natural listings, organic listings are webpage listings that appear on a Search Engine Results Page solely because the search engine Algorithm deems them relevant to the Query. Organic listings can contain Paid Listings, but only if they fulfill the same requirements as organic listings. The best way to improve a site's organic listing Position is through Natural Search Engine Optimization.

Search Engine Results Page (SERPs)

Also known as a results page, the search engine results page is the collection of ranked Listings displayed in response to a search engine Query.

Dofollow and Nofollow links :- These are types of links used in link building for effectiveness of links. Placing a nofollow link at the bottom of the page has least impact and when placed at the top of the page, it carries some impact.

Nofollow links :- Robots Meta Tag : <meta name=”robots” content=”nofollow” />

Link Attribute : <a href=”http://www.google.com” rel=”nofollow”>

This tells search engines not to count the link in terms of ranking pages.

Try to keep noindex attribute for pages like contact and nofollow attribute for affiliate links on your blog posts. If you are linking to any spam website for any reason, use nofollow link attribute.

Dofollow Links :-  By default all natural links are DoFollow. More Dofollow links from high PR websites helps in increasing our page rank.

Dofollow links are good and affect your page rank and nofollow links do not.  Any easy way to picture it, is by thinking of dofollow links as votes for a specific keyword/title.  The more dofollow links with a particular title, the higher that url will rank in search engines for that keyword.

Types of links :- Reciprocal and non reciprocal.

Interesting facts :-
Oldest Search engine Altavista is now attached with yahoo.