Google and Yahoo Search Technology Compared
Search Engine Journal Google and Yahoo Search Engine Technology Comparison: "Google and Yahoo Search Engine Technology ComparisonGoogle Search
Google look at hundreds of factors – both on the page and off the page (such as inbound links). They use hundreds of algorithms to perform these calculations. Essentially there should be one algorithm per factor. The algorithms weight the pages, and assign their values. These values are then stored for later use.
When a user performs a query, yet another set of algorithms weigh the previously calculated values against one another to determine overall relevance. Results are then outputted to the users browser...
...the factors Google has used to rank pages has changed over time. They are placing less emphasis on PageRank, but it is still important. Its important to note that moving different factors around within the calculation can greatly impact a site’s rankings. For example, if the site has a high PageRank, but a low keyword density, it may rank #1 if PageRank affects the calculation later, however the site may disappear from the results if PageRank is considered earlier.
And this is probably what is happening now – Google has essentially moved the PageRank factor to somewhere else in the final calculation. Remember, there are likely hundreds of factors affecting rankings. By rearranging the order in which they are applied to the final rankings can have a dramatic impact on overall placement on the search results page.
Google also appears to have moved from a once per month update to a more perpetually updating index. We only rarely notice the changes happen, but they do happen on a more incremental level, with more major updates happening less frequently.
I guess one could view Google as a series of layers – each layer building on the work performed by the layer before. The uppermost layer is the only one we are exposed to via the browser, however that page that you see would not exist without the work performed by the lower layers.
Yahoo! Search
- While no one other than Yahoo!s engineers know for sure, we can speculate that Yahoo! search technology works very similar to Google’s...Yahoo! is so difficult to gauge is because they haven’t really built a search engine from the ground up like Google or MSN. Of course the Yahoo! search you see is unique unto itself, however Yahoo! has built its search on the backs of other technologies they have purchased in previous years...
Yahoo! built their own search, cobbling together features from all the technology they owned.
They had the super fast Inktomi and Altavista crawlers, as well as the surprisingly good Alltheweb and Altavista ranking algorithms. So they mashed that all together to get Yahoo! Search.
Yahoo! Search isn’t much different that Google. Their own website says that they analyze pages using many factors to determine relevance to a search query...over the past few months we’ve noticed a subtle shift from homepage only rankings to multiple site pages ranking where the home page once ranked.
In addition, they tend to rank inbound links differently than Google. When you perform a link check on Google and the same check on Yahoo! the Google results almost always tend to be lower. Google says this is because they only show a snapshot of the “relevant” links whereas Yahoo! shows them all regardless of relevance.
"
posted by Jen @ 6:15 AM
<< Home