Yesterday, the Google Webmaster Help team posted another video by Matt Cutts - this one was named What happens if I link to a good page that later becomes spammy?
In short, Google's Matt Cutts said, you should not worry about it. He qualifies that by saying that if you link to a ton of bad sites, then yes - it is an issue. But if you have a few bad or dead links then it is not something you should worry about.
Here is the video:
This reminds me of when Ask Jeeves became a porn star. In short, Ask retired Jeeves in 2006 and made a web site for his retirement at jeevesretirement.com/desk. They intentionally or un-intentionally did not renew the domain name a couple years later and a really nasty adult site put content on it. Yet, Ask.com and all these other publications - good sources - linked to the domain name. Those sites did not suffer from linking to this one bad site.
Here is the video transcript:
0:00 SPEAKER 1: Today's question comes from Toronto.
0:03 MrTVTL has a pretty long question: Site A links to Site
0:08 B because Site B has content that would be useful to Site
0:11 A's end users, and Google indexes the appropriate page.
0:15 After the page is indexed, site B's content changes and
0:18 becomes spammy, so does Site A incur a penalty in this case?
0:23 OK, so let's make it concrete.
0:24 Suppose I link to a great site.
0:26 I love it, and so I link to it.
0:28 I think it's good for my users.
0:30 Google finds that page.
0:31 Everybody's happy.
0:32 Users are happy.
0:34 Life is good.
0:35 Except now, that site that I linked to went away.
0:39 It didn't pay its domain registration or whatever, and
0:41 now becomes maybe an expired domain porn site, and it's
0:44 doing some really nasty stuff.
0:46 Am I going to be penalized for that?
0:49 In general, no.
0:50 It's not the sort of thing where just having a few stale
0:52 links that happen to link to spam are going to get you into
0:54 problems. But if a vast majority of your site just
0:58 happens to link to a whole bunch of really spammy porn or
1:01 off-topic stuff, then that can start to affect your site's
1:05 We look at the overall nature of the web, and certain amount
1:09 of links are always going stale, going 404, pointing to
1:13 information that can change or that can become spammy.
1:15 And so it's not the case that just because you have one link
1:18 that happens to go to bad content because the content
1:20 has changed since you made that link, that you're going
1:23 to run into an issue.
1:24 At the same time, we are able to suss out in a lot of ways
1:28 when people are trying to link to abusive or manipulative or
1:32 deceptive or malicious sites.
1:34 So in the general case, I wouldn't
1:37 worry about it at all.
1:38 If you are trying to hide a whole bunch of spammy links,
1:41 then that might be the sort of thing that you
1:42 need to worry about.
1:43 But just a particular site that happened to go bad, and
1:47 you don't know about every single site, and you don't
1:49 re-check every single link on your site, that's not the sort
1:51 of thing that I would worry about.
1:53 Hope that helps.
Forum discussion at Google+.
Image credit to ShutterStock for broken chain