The most common causes for any 'sudden drop' in PageRank

My homepage recently suffered a PageRank drop. Just prior to that,
we added a large number of outbound links and are now wondering if
that was the cause. Are there limits to how many links we should have
on our pages?
Answer:
It's unlikely that adding those outbound links was the cause of your
PageRank dropping. A PageRank drop is nearly always caused by a drop in
external links pointing to a page, not by the links pointing out from the page.
Those incoming links either became partially devalued due to losing inbound
links of their own, or they lost their value completely by being removed or
having the nofollow tag applied to them.
You should examine your inbound links looking for recent changes. You can
do this using our Site Strength Indicator tool (log in with this month's
password). Losing high PageRank inbound links (or if those linking pages
lost PageRank themselves) is the most likely reason for this sudden
PageRank drop.
And, because high PageRank links are so important, all it takes to have an
adverse effect on rankings is to lose just a few.
Bear in mind that it is also possible to dilute the link juice (PageRank) pointing
at your own
site's pages by adding a large number of outbound links all at once. This also
could adversely effect your PageRank.
However in most cases this does not cause enough of a change in
PageRank flow to see any negative effects unless the links you've added are
sitewide (i.e. linking out from every page on your site). For example, if you
have 5-10 outbound links in the footer of every page on your site, that could
have the effect of siphoning PageRank away from your site. In that case, you
may want to limit those outbound links to just a few of your pages, such as
your homepage, rather than making them sitewide.
While it's true that linking to other sites is an important part of building the
social relationships that result in links back to your site, you must also
structure your outbound links intelligently. To learn more about sculpting the
flow of PageRank on your site, see our recent report...
How to Boost your Rankings by Sculpting Your PageRank with
Nofollow
Sculpting your PageRank is a powerful tool for any webmaster. When used
correctly it can give you a much-needed advantage over your competition.
August 2008
Year Twelve
Issue 139
Page Six
Table of
Contents
The most common causes for any 'sudden drop' in PageRank - Search E... http://www.searchenginenews.com/se-news/content/2008/08/the_most_...
2 of 2 8/12/2008 4:17 PM
Finally, note that, as the total number of Internet webpages grows, Google is
always recalculating PageRank for every existing page in their index. It's
possible that you have just as many links as before—but since those links
now represent a smaller percentage of the total pool of webpages, you may
see your PageRank drop. Simply adding new links at a slower rate than in
the past can also cause a PageRank drop.
Most importantly, remember that PageRank does not equal rankings. We've
actually seen many cases where a page's PageRank went down, but their
rankings and traffic went up. So unless your rankings and traffic have
plummeted, you should not stress yourself over a PageRank dip.