Google vs. MSN and Yahoo

A lot of SEO is trial and error. Company's and experts can tell you they understand search engine algorithms, but because they're constantly changing, the truth is, it's hard to say for sure what the current criteria is for each search engine. Sure, we know the basics: back-links, copy, etc., but what are the other factors involved, and how much of a role do they actually play in determining search engine rank?

One thing I've found time and time again is Yahoo and MSN's response to keyword density. Whenever any significant change is made to our main page's keyword density, I notice fluctuations in rank almost immediately. On the other hand, Google seems to almost not care at all. Since most of my research revolves around Google, I've noticed that some sites rank very well with an above average keyword density, while others do well with a below average percentage. There are many myths about Google's keyword density tolerance, but personally, I think they just don't really care as long as it's within a reasonable percentage. I say "reasonable percentage" because Google seems to be pretty keen on identifying and penalizing sites that are clearly spamming.

Another thing I've found time and time again is the way Google analyzes back-links compared to Yahoo and MSN. It seems that Google is also quite keen on identifying a back-link's relevance and quality while Yahoo and MSN seem to lean more toward quantity. I come to this conclusion by seeing a wide variance in the way Google ranks sites compared to the other 2.

In general, sites that rank well in Yahoo and MSN rarely rank as well in Google. The conclusion is two-fold:

1. Yahoo and MSN place a higher weight on keyword density


2. Google analyzes back-links with a broader lens than the others

Anyone who follows SEO closely will tell you that this hypotheses is nothing new, but because SEO is difficult to prove, hard evidence is the only we really have.