A number of websites are (or were) planning to “go black” this week while the U.S. Congress discusses issues related to the Stop Online Piracy Act (SOPA) and the Protect IP Act (PIPA). The website blackouts are part of a larger social media effort against the bills that our Greg Finn wrote about this morning on Marketing Land.

You may be thinking about joining the website blackout movement, but yikes … what about the SEO implications? How do you take your site offline in protest without messing up your visibility in Google’s search results?

Well, Google’s Pierre Far shared several tips earlier today on Google+ in a post called “Website outages and blackouts the right way.”

In short, the advice is to use a 503 HTTP status code to tell spiders that the website is temporary unavilable. With a 503 status, Google won’t index the content (or lack thereof if you’re blacking out your site) and it won’t consider the site as having duplicate content issues (when all of the pages are blacked out).

But Far adds a couple important caveats to this advice regarding the robots.txt file and what will happen in Webmaster Tools if Google finds your site blacked out. Another Googler, John Mueller, adds additional information in the comments, so you’ll want to read the original Google+ post if you’re thinking about blacking out your website this week for SOPA, or in the future for any other reason.

Of course, also keep in mind that Bing may not handle things the same way if you do blackout your site.