Official statement - what Google feels about hidden text

A nice writing by a Google employee on what they feel about hidden text with examples:

"In our "Popular Picks" thread, Burchman asked for some clarification on what Google considers to be hidden text, as our Webmaster Guidelines explicitly state that you should avoid hidden text or hidden links. We have a few examples of how text can be hidden in this Help Center article: https://www.google.com/support/webmasters/bin/answer.py?answer=66353

As I've noticed other users with similar questions in this group, such as "What if my navigation menu uses display:none to hide text until a button is rolled over?" I figured this would be a good topic to cover in "Popular Picks." The reason we perceive hidden text as a problem is that it serves content to search engines which users don't see, and presenting different content to search engines and users makes it more difficult to properly rank pages. If we detect that this text is intended to deceive search engines, there could be a negative effect on how your site is indexed and ranked in Google, including removal from our index.
Because such strong action may be taken on sites violating this guideline, it's understandable that many webmasters have expressed concerns about the possibility of Google incorrectly detecting legitimate content as hidden text. When trying to figure out if a page may have hidden text that Google would consider malicious, start by thinking about why the guideline was written in the first place: Google wants to see what the user sees. If the text that Google sees is the same that a normal user is supposed to see, then you should be good to go. If Google is seeing text that is intentionally hidden from the user in an effort to manipulate search engine rankings, you have some work to do.
Let's try this approach with a page you may have seen before: https://www.google.com/

In the top-left corner, you'll see a line of text: "Web Images Video News Maps Gmail more."
Google sees this text, and so do you, the user. So far, so good.
Next, let's make sure nobody wrote "search engine search find crawl index rank" in white text on the white background, with the intention of ranking for those terms. Google would see that, but a normal user wouldn't. Take off your "normal user" hat for a second and do a "Select All" on the page (by hitting CTRL-A on a PC, or COMMAND-A on a Mac, for instance). This will make any white on white text appear. As you can see, no hidden text.
But let's try one more thing: Render the page again without CSS enabled. The Web Developer extension for Firefox lets you do this pretty easily. Without CSS, you'll see several words we didn't see before: "Blog Search Blogger Books Calendar Documents Finance Groups Labs Orkut Patents Photos Products Reader Scholar."
You may have also noticed that these words appear in Google's text- only cache of itself, which is a good indication of how Google "sees" a site. But before you blog about your discovery of hidden links on a PR 10 site =), take a look at the page again with CSS enabled. This time, click on the "more" link, and voilà, the no-longer-hidden text appears. This text is part of the page's functionality, and it is meant for the user to read and use, not just for search engines to index. This text adds value for the user, which Google rewards, so Google would not hurt this site's ranking or remove it from the index for that reason. Many sites use similar methods for navigational menus and other functional elements, so please rest assured that the existence of display:none on your site is not on its own a one-way ticket out of Google's index.
When thinking about your own site, ask yourself if all of the text is there for the user. If the answer is "yes," great job! If the answer is "no," do your best to change it to a "yes," and call on your webmaster community (this group!) for advice if you need it. CSS menus and white space without hidden text should not be a cause of concern when it comes to Google indexing and ranking; the only thing you should be concerned about is how they affect your visitors.
In the "Popular Picks" thread we asked for non-site specific questions, but now that this has been separated into its own thread, here's your chance to ask about a site you are still unsure about. Please also let me know if you would like further clarification on particular aspects this topic. "

Source: Google Groups

Labels: Google Blog