| A dangling
link is a link to a page that has no links going from it, or
a link to a page that Google hasn't indexed. In both cases Google
removes the links shortly after the start of the calculations
and reinstates them shortly before the calculations are finished.
In this way, their effect on the PageRank of other pages in
minimal.
The results shown in Example 2 (right diag.) are wrong because
page B has no links going from it, and so the link from page
A to page B is dangling and would be removed from the calculations.
The results of the calculations would show all three pages
as having 0.15.
It may suit site functionality to link to pages that have
no links going from them without losing any PageRank from
the other pages but it would be waste of potential PageRank.
Take a look at this example. The site's potential is 5 because
it has 5 pages, but without page E linked in, the site only
has 4.15.
Link page A to page E and click Calculate. Notice that the
site's total has gone down very significantly. But, because
the new link is dangling and would be removed from the calculations,
we can ignore the new total and assume the previous 4.15 to
be true. That's the effect of functionally useful, dangling
links in the site. There's no overall PageRank loss.
However, some of the site's potential total is still being
wasted, so link Page E back to Page A and click Calculate.
Now we have the maximum PageRank that is possible with 5 pages.
Nothing is being wasted.
Although it may be functionally good to link to pages within
the site without those pages linking out again, it is bad
for PageRank. It is pointless wasting PageRank unnecessarily,
so always make sure that every page in the site links out
to at least one other page in the site.
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