Latent Semantic Indexing (LSI) and SEO: New Methods for Choosing Keywords and Inbound Link Strategies

Richard CummingsBlogging, Featured, SEO/Site Promotion2 Comments

A relatively new concept called Latent Semantic Indexing will change the way that SEO is performed.  If you stick with your “older” methods of choosing keywords and creating inbound links, you may find your pages slowly disappearing from the google index.

In the past (and still today), many SEO professionals find a popular keyword, fill the page with that keyword, and create a massive amount of inbound links using exactly that keyword.

This technique still works today.  In fact, I recently had a frustrating experience with it.  I was searching for Airfrance Flight 447, the plane that crashed over the Atlantic, because I wanted to find out more information as I had a friend who may have been on this flight (luckily he wasn’t).  The fifth entry down in google looked promising so I clicked it and it took me to a page that wanted to analyze my system because it “appeared” to be infected.  You know that game…they then tell you that you need their program to get rid of the malware on your system.  This is bad for the web and even worse for google.

Enter Latent Semantic Indexing.

Latent Semantic Indexing

Latent Semantic Indexing is a technology employed by Google in an attempt to give you better, more natural, search results.

Google is in the business of providing the best search results.  In spite of the fact that they make extremely cool products and give them to us for free (think Google Earth), 80% of their revenue still comes from their search engine.

Thus, if I search for a term, and receive only useless pages filled with ads, I will be a frustrated user and might look elsewhere for a search engine that provides better results.

Google needed a better way to provide search results that could not be so easily manipulated as in the example above.

Latent Semantic Indexing:  A Quick History

In 2003, Google purchased Applied Semantics, a company dedicated to delivering more effective advertising for web sites.  Initially, this purchase was a move to thwart one of Google’s largest advertising competitors, Overture, who has since been purchased by Yahoo and has become known as Yahoo Search Marketing.

Over time, Google has taken the engineering concepts from Applied Semantics and implemented them into their core search functionality.

This fundamental shift marks a move away from keyword-focused searched results to theme-focused searched results.

Latent Semantic Indexing:  How It Works

LSI does not look exclusively at the keywords a webpage uses but at the theme of a page.

For example, let’s assume that you are creating a webpage with the keywords being download top music.  In the past, you would create the page using this term frequently and perhaps some variations on the term like download music, music downloads, top music downloads.

This strategy will no longer be as effective with the new LSI implementation.  LSI uses an algorithm to look for related keywords to determine the value of your page.  This approach provides better results.

In looking at this music example, can you identify other words that you should use given this new LSI paradigm?

We can begin this process by asking some questions.  Where do people download music from?  In what format do people download music?  How much do people want to pay for their music?  What are other names for music?

Can you see where this is going?  In asking these questions, we come up with related terms like online, Internet, mp3, mp4, free, inexpensive, songs, tunes, etc.

Thus, LSI increases the value of a webpage with these related keywords and devalues a page that simply has variations of the keyword such as download music.

This has great SEO implications.

LSI and SEO:  Brothers in Arms

You need to be aware of how LSI works in order to do effective Search Engine Optimization.

As we see in the example above, you must expand your keyword research efforts beyond what you would have in the past.  No longer can you simply use 4 variations of the same term.  You need to know all the related terms on the subject.

How can you discover related terms?  Well, in the music example, we simply asked basic questions to come up with some common sense answers.  There is a much quicker way though.  Wordtracker provides a related keywords feature that expedites this process.  (I actually used it to formulate the questions above.)

The term Latent Semantic Indexing has gained a lot of momentum in recent months as google continues implementing features.  But the real question is:  How will LSI affect my page placements within google?

Well, we have seen how you should create your future pages–simply make sure that your pages reach beyond just the keyword that you are targeting by using many similar related keywords.  This will result in a page that is more theme-focused and less keyword-focused.

But what about the pages that you have already created?

We know that re-doing web pages is an arduous task and you don’t want to have to do this.  There is good news and bad news.

The good news is that you should have been doing your pages this way for the last several years.  In the SEO community, we have known for some time that a page with just one keyword or phrase, and inbound links focused solely on that keyword, will eventually get your page penalized.

Google always attempts to weed out unnatural sites over time.  A webpage with the same anchor text on every inbound link is unnatural.  What are the chances that everyone links into a page with the same anchor text?  If you have been using one or two keywords or phrases, and inbound linking solely on those terms, you are in for a world of hurt.  You either need to revise your pages and create new related keyword inbound links OR watch your pages slowing disappear from their current google standing.

However, if you have been practicing solid SEO by creating informative pages with naturally relevant related keywords, your pages will be fine and you do not need to do any revisions.

Latent Semantic Indexing and SEO:  Summary

We often like to assign big, fancy terms to relatively simple concepts.  Latent Semantic Indexing, or LSI, falls into this category.

Essentially, it means that your pages need many thematically related keywords, not just your targeted keyword.

Frankly, SEO experts have known this for a long time.  A long detailed page about any topic, combined with good inbound links, will always yield the best google results.  On top of that, a long detailed page will always, naturally, have an abundance of related keywords.

Thus, Latent Semantic Indexing is nothing new and you should not need to considerably alter your SEO approach.

However, if you are narrowly targeting one or two keywords or phrases, with skimpy, shallow content, you need to know this.

You must change your SEO strategy…or change your career!

2 Comments on “Latent Semantic Indexing (LSI) and SEO: New Methods for Choosing Keywords and Inbound Link Strategies”

  1. Richard, thanks for that explanation. I read about LSI on Wikipedia and my head was spinning. This made it a lot easier.

  2. That was so helpful, so many thanks! I am quite a newbee at SEO but really enjoying the ride. I have been submitting articles using just 2 keywords for my client, so as I understand from your article I need to mix it up a bit. Thanks also for the “wordtracker”link. There seems to be so many SEO tools out there, but one needs to know what you are doing first- one thing is for sure, nothing worth having is easy!!


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