Retrieval and ranking

[johnnight]

I was reading a SEO book and I found that, I think its helpful.

Source: Amazon.com: SEO: Search Engine Optimization Bible (9780470175002): Jerri L. Ledford: Books

Retrieval and ranking
■ Location: Location doesn’t refer here to the location (as in the URL) of a web page.
Instead, it refers to the location of keywords and phrases on a web page. For example,
if a user searches for ‘‘puppies,’’ some search engines will rank the results according to
where on the page the word ‘‘puppies’’ appears. Obviously, the higher the word appears
on the page, the higher the rank might be. Therefore, a web site that contains the word
‘‘puppies’’ in the title tag will likely appear higher than a web site that is about puppies
but does not contain the word in the title tag. This means that a web site that’s not
designed with SEO in mind will likely not rank where you would expect it to rank.
■ Frequency: The frequency with which the search term appears on the page may also affect
how a page is ranked in search results. For example, on a page about puppies, one that
uses the word five times might be ranked higher than one that uses the word only two or
three times. When word frequency became a well-known factor, some web site designers
began using hidden words hundreds of times on pages, trying to artificially boost theirpage rankings. Most search engines now recognize this as keyword spamming and ignore or
even refuse to list pages that use this technique.
■ Links: One of the more recent ranking factors is the type and number of links on a web
page. Links that come into the site, links that lead out of the site, and links within the site
are all taken into consideration. It would follow, then, that the more links you have on
your page or leading to your page, the higher your rank would be, right? Again, it doesn’t
necessarily work that way. More accurately, the number of relevant links coming into
your page, versus the number of relevant links within the page, versus the number of relevant
links leading off the page has a bearing on the rank that your page gets in the search
results.
■ Click-throughs: One last element that might determine how your site ranks against others
in a search is the number of click-throughs your site has versus click-throughs for other
pages that are shown in page rankings. Because a search engine cannot monitor site traffic
for every site on the Web, some search engines monitor the number of clicks each search
result receives. The rankings may then be repositioned in a future search, based on this
interaction with users.

 

[AliceandMosee]

From what I understand backlink spam is less sought after by google for SEO, while high quality backlinks are still highly usable, as long as they're dofollow of course.