|For quite some time I have puzzled over why my testing of the impact of link order on a web page as an SEO factor resulted in inconsistent results. My hypothesis was that link order on a page impacted the link juice passed by a hyperlink. Occasionally, I would think I had found proof that link order was an SEO factor, but then would be unable to validate the results with follow on tests.
I think I may have finally stumbled upon an answer to why it often seems that link order is an SEO factor. The reason link order seems to be an SEO factor may be because it is closely related to two factors that most likely do have an impact on the weight the search engine algorithms give to a link: 1) click rates; and 2) page segmentation.
As a search engine algorithm analyzes the signals on a page to determine the subject of a website and specific web page, the ratio of clicks to other page on the site potentially provides valuable information about the link and the web page. As an example, the home page of Koffler Sales offers a particularly graphic example of how link order impacts click rates and signals the importance of links. As shown below, the first link in the main content section of the site generates the most clicks (13%, and the order of the other links correlates to click thru rates with some of the links on the second row of images only getting 10% as many clicks).
Link Order - Impact on Click Thru's
Thus, utilizing click rates as a signal to determine the weight passed by links would correctly assign the most weight to the Stair Treads page. Assuming that the search engines are indeed using click rates as a link weighting factor, it would explain why link order would appear to be an SEO factor. Link order and link prominence have a huge impact on click rates, as most visitors scan the web page from top left to bottom right.
Although I cannot close the circle with indisputable proof that click ratio of a link is an SEO factor, support for this conclusion is provided by viewing sitelinks on Google (the links shown below some sites in search result snippets). Sitelinks frequently include links to "careers" pages and other types of pages that attract high click ratios despite only a limited number of inlinks. The high frequency of clicks on "careers" pages by job seekers seems the likely reason that these types of pages with only a limited number of inlinks often show up as sitelinks. It does not require too great a leap of logic to jump to a conclusion that high click ratios are a factor in both selection as a sitelink and in the weight passed on by a link.
Sitelink including "Careers" page
Page segmentation is a second factor that is related to link order that impacts SEO. Page segmentation assigns differing weight to links based on the section of a page they appear in. The search engine algorithms recognize sections of a web page, such as the header, footer, navigation bars and main content section. While it is generally recognized that footer links do not pass as much authority as links in the main content section of a web page, additional segmenting of the main content section may also be at play.
A Google patent filed in 2004 (and granted this year) indicates that links in “different semantically distinct regions may be assigned different weights.” Microsoft also has filed a number of patent applications for identifying blocks in web page to improve search results.
Thus, while link order in and of itself is not an SEO factor, link position based on page segment is an SEO factor.
What Does Google Say About Link Order?
In a Google Webmaster Help video, Matt Cutts states that "in general I would not worry about link order or first link on a page. Google will parse a page to find the links that are relevant". However, he modifies that statement by also indicating that "I would not make the link I care about the most the 1,001 link". Thus, while this statement by Google's chief spam cop is open to a bit of interpretation, it does seem to put the kibosh on speculation that link order is a factor in the Google search algorithm.
The prominence of a link on a web page may have an impact on the weight the hyper link passes on to the web pages to which it links. More testing is required to either prove or disprove this hypothesis. However, until more quantitative information is available in regard to this theory it may be appropriate to place links that are most important from an SEO standpoint in prominent click attracting positions on web pages. As long as doing so does not negatively impact the usability of the web page, you are unlikely to do harm and may produce a link authority boost.