Many webmasters reported that Google's spider
started to index their external CSS files. What are CSS files,
why does Google index them and how can this affect your rankings
on Google and other search engines?
are CSS files?
(Cascading Style Sheets) files allow webmasters to specify the
layout of a web site without touching the HTML code. A good
example is the CSS Zen Garden site.
that web site, you can change the complete look of the site
by selecting different style sheets. The HTML code of the page
is always the same, only the CSS file that is used to display
the HTML code changes.
the problem with CSS files?
allow webmasters to design their web pages without touching
the HTML code. That also means that webmasters can use that
technique to hide content from their web site visitors.
can put keyword rich content in the HTML code of their web pages
that search engines can index. The same text can be hidden from
human web surfers by using CSS.
means that search engines see something totally different than
human web surfers. Unfortunately, some webmasters try to fool
search engines with that technique.
do search engines do about this problem?
engines don't want to be fooled by webmasters. For that reason,
they started to index CSS files. If search engines find anything
that looks like spamming in a CSS file, they might penalize
the corresponding site.
can you do to avoid problems with your CSS files?
it's not clear yet what search engines consider spamming and
what not. There are many legitimate uses for hiding text on
a web site so it's hard to tell what search engines will penalize.
a rule of thumb, don't try to cheat search engines. If you do
something explicitly to cheat search engines then chances are
that search engines will detect this and penalize your site
sooner or later.
yourself if it is really necessary to hide text on your web
site. If it might be misinterpreted as spamming by human web
surfers, don't hide text on your site. Don't use shady techniques
to promote your web site.