A presentation explaining how search engines work and the difference between SEO and PPC.

1. How Search Engines Work
SEO v PPC
Search Engines have been around since 1994 when WebCrawler launched, and have always operated in a similar
way. How they work today has been almost entirely shaped by Google which launched in 1998.
Google now control about 90% of the UK search market, so this article is focusing on them.
Search engines are designed to help the user find the information they are looking for quickly on the internet. They
are able to do that because the internet is essentially a mass of text which can easily be scanned to see what
pages have the content most relevant to the users query.
To analyse the whole of the internet for the answer to each and every search query would take a long time. To
ensure they deliver results to the user quickly, each search engine sends out “crawlers” (also known as “spiders” or
“bots”) which are little programmes that run around the internet picking up the key details of each page they crawl
through. The information they collect is used to create an “index” which the search engine can easily analyse to
bring back a result for the user quickly.
Over the last 10 years the way in which search engines analyse their index has become more intelligent so that the
results which are presented relate more closely to the search query. Rather than bring back results graded on how
many times the search term appears on the page, they now:
 grade different types of content differently
 assess the context in which the information is provided
 assess how important that page is to that subject
Google achieve this through two factors:
1. PageRank (Page for “Larry Page” one of the founders, not “webpage”)
2. Hypertext-Matching Analysis
PageRank measures the importance of a web page – in basic terms by:
 Counting the number of other pages linking to the page in question (this can include links from within the
same website)
 The worth of each link is calculated based on the PageRank of the page the link comes from
By downloading the Google toolbar you can find out each of your webpage’s PageRanks.
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2. Hypertext-Marching Analysis analyses the content of the page and assesses its relevance in order to do this. It
looks at everything including:
- Text
- Fonts
- Where the content is
- Meta data
- Subdivisions
- Content of neighbouring pages
By combining these 2 pieces of Analysis, Google is able to bring back relevant results.
The whole process is often referred to as the “algorithm” – a very mysterious thing!
All that analysis costs a lot to do and only drives the “free” results (the ones on the left hand side) therefore
bringing in no income. In order to make money, Google provides paid for results on the right hand side of the
page.
How Paid Search Works
Pay per click / PPC was invented by Overture (a part of Yahoo) in 1996. Google were sued for allegedly imitating
Overture’s model, and bought a perpetual license in return for shares.
Essentially paid search is an auction. The advertiser decides how much they are willing to pay to appear when a
keyword is searched on, and which advert they want to appear in that eventuality. Originally the person who was
willing to pay the most got the best position on the page.
Nowadays it depends both on how much you are willing to pay and on your Quality Score. Your Quality Score
varies for every keyword you bid on and is based on the following:
 The click through rate of that keyword
 How many click through compared to those who see it
 The relevancy of your adtext to the keyword it appears for
 The historical performance of your adwords campaigns
 How the adwords campaign is structured
 The relevance of the landing page to the adtext
 The relevance of the landing page to the keyword
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3. Search Engine Marketing – SEO v PPC
Search engine marketing covers both maximising your presence in the natural, free listings via SEO (Search Engine
Optimisation) and the paid listing in a PPC (Pay Per Click):
 Search Marketing via SEO relates to making the most of PageRank and HyperText-Matching Analysis to
get your website high in the results for selected keywords / keyphrases
Search Marketing via PPC relates to building and optimising a campaign to put your website in profitable places on
the search engines
These are 2 very different methods of achieving search engine success that should be run in tandem so that the
results of each can be used to improve the other. The key differences are outlined below:
SEO PPC
- Very versatile
- "Free" (you don't pay for every single - Very scientific
click) - Greater control
Pro's
- Work done impacts on all search engines - Quick turnaround (results in days)
- Some consumers prefer it - You can bid on any keyword you like, and as many as
you like
- Little control
- Unscientific
- Results trusted less by consumers
- Difficult to analyse
- You pay for every single click
Con's - Have to focus on limited
- You have to manage each search engine separately
- Keywords/keyphrases
- Optimatisation can be resource intensive
- Usually 3-12 months before impact is
seen
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