The real question now becomes how pervasive this is going to become. Is Google going to start crawling everyone’s CSS? Or are they simply going to trigger off of manual or algorithmic flags to do this for some sites? Or for that matter, are they going to start doing some random crawls of CSS on some sites as a spot check?
In this post by Barry he quotes “pageoneresults” in a WebmasterWorld forum:
Google has a hard enough time now dealing with html/xhtml. Parsing CSS files and determining whether something is hidden or not is not a solution. Now the bot would need to determine why that CSS exists. There are many valid uses of display:none or display:hidden.For those who may be hiding things through CSS or negatively positioning content off screen to manipulate page content, I surely wouldn’t do that with any long term projects.
The penalty for getting busted using this technique I would imagine is a permanent ban. No if’s, and’s, or but’s, you’re history. You’ll need a pardon from the Governor to be reconsidered for inclusion.
It may indeed be hard to algorithmically determine an illicit use of display:none or display:hidden, v.s. a legitimate one, but it certainly can be used as a flag.
We need to remember that this all operates in the context of “trust”, a topic that Matt McGee does an excellent job of discussing in his recent post on that topic. There are many trust flags that search engines look for. Usually, no single bad thing is going to lead to your being penalized (unless, it’s REALLY bad). But many things can be used as flags:
- Buying links
- Too many reciprocal links
- Abnormal changes in rates for adding links
- No trusted links
- NoCrawling your CSS files
- Using display:none or display:hidden in your CSS file
All of these things can be used as triggers. Amass too many flags, and a site becomes worth a review. And, of course, some of these things trigger algorithmic penalties (e.g. too high a percentage of reciprocal links).
Of course, Google can take a simpler approach, based on creating FUD. Read in a bunch of CSS files here and there and ignore them. Gets us all talking about it wondering what they are doing doesn’t it? Be that as it may, I would take pageoneresults statement above to heart, when talking about hiding things with CSS: “I surely wouldn’t do that with any long term projects”.