There is an incredibly strong link between Usability and SEO. First,
you have to start with the knowledge that the business of the search
engines is enhanced by having the most relevant results in their index
(the ones that do in fact answer the user’s question quickly), and this
means that usability matters to them. Therefore it is in their
strategic interest to develop an understanding of a site’s usability.
There are many ways that the search engines can collect basic
usability data. For example, do users bookmark your site at major sites
such as del.icio.us? Do you have a high bounce rate (people who view
only one page, or who don’t stay long on the site)? These are just a
couple of basic things that a search engine can look at to measure
Second, usabilty is a key factor in driving the acquisition of high
value links. Trying to get a major university or a government site to
link to yours? What do they see when they come to the page you are
trying to get them to link to? Do they understand it right away? Or
does it confuse them?
At an architectural level, having a clean site hierarchy and an
easily understood navigation structure also benefits both usability and
SEO. This means things like a logically thought through hierarchy that
matches up with the nature of the content you are providing in an easy
to understand way. It means having a consistent global navigation
structure, and a breadcrumb bar.