Should I add rel=”nofollow” to links that are included with my widget?

Matt's answer:

Today’s question comes from Madrid. Christian asks, what should we do with embeddable code in things like widgets and infographics? Should we include the rel nofollow attribute by default, or advise the user that the code includes a link and give him the option of not including it? So my answer to this is colored by the fact that we have seen a ton of people trying to abuse widgets and abuse infographics. We’ve seen people who get a web counter, and they don’t realize that there’s mesothelioma links within there. So I’ve done a previous video where I talked about the criteria for widgets. Does it point back to you or to a third party? Is the keyword text sort of keyword rich and something where the anchor text is really rich, or is it just the name of your site? All that sort of stuff. But I would not rely on widgets and infographics as your primary way to gather links. And I would recommend putting a nofollow, especially on widgets, because most people when they just copy and paste a segment of code, they don’t realize what all is going with that. And it’s usually not as much of an editorial choice because they might not see the links that are embedded within that widget. Depending on the scale of the stuff that you’re doing with infographics, you might consider putting a rel nofollow on infographic links as well. The value of those things might be branding, they might be to drive traffic, they might be to sort of let people know that your site or your service exists, but I wouldn’t expect a link from a widget to necessarily carry the same weight as an editorial link freely given where someone is recommending something and talking about it in blog post. That sort of thing.

by Matt Cutts - Google's Head of Search Quality Team

Original video: