Understanding nofollow links

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Michelle Dear: I officially have a dumb SEO question. ;
  
  I am really trying to understand nofollow links, and I just don't. Here's where my brain goes to mush. Let me give you an example.
  
  Let's say Website A (WA) has a link in Article1 (A1) to Website B (WB) Article 3 (A3).  ;
  
   ;  ;  ;  ;  ;  ;  ;  ;  ;WA(A1)--->WB(A3)
  
  Now, I'm reading about nofollows on backlinks. I understand that it's not required. And I understand some of the reasons why you may set them up (spammy blog comments.) But what I don't understand is this:
  
  1. Which website sets up the nofollow in this particular example?
  
  2. Why would they do this? Just examples for reasons please. (I understand if the authority is crap, or it's not a trusted source.)
  
  2b. Where do they put the nofollow?
  
  3. Let's say I create content (article) that references something awesome in an article by Barry Schwartz. Do I have to get his permission just to refer to an article of his and link to it? Back in the day, we didn't have to do that. If I don't have to do that, is this where I put in a nofollow? Or is this something he takes care of? How would he know I am even linking to him? Do I tell him in advance?
  
  4. I've read about how some sites can do an overarching nofollow or something? Does this mean that anyone that creates a link to their content basically doesn't hurt their SEO?
  
  I suppose that my questions indicate I need a bit of a primer on nofollow for the source link and the backlink?  ;But I'll be honest. I've read tons, and my brain just isn't getting it.
• 
  Jim Munro: Good on you for leaving yourself wide open on this one, +Michelle Dear, I think you've demonstrated an important point. There is so much information and misinformation intertwined that it's virtually impossible to interpret and evaluate alone.
  
  Dumb SEO Questions exists to provide a forum for clarification and as long as we all continue to label our opinions as opinions and also back up anything we contend to be a fact with links to universally-accepted guidance, we have a fighting chance of being useful.
• 
  Michelle Dear: Thanks +Jim Munro ;. This one had me going in circles. Can't wait to get it all straightened out!
• 
  Jim Munro: I'm looking forward to the answers. We should make this a challenge to deliver the most  ;definitive answer in the shortest number of words. :)
• 
  Michelle Dear: +Jim Munro ;Or even a graphic. That's what's missing in all of my studying so far. Lots of text, no visuals to explain it to me.
• 
  Jose Terrier: Good question +Michelle Dear​​​​​​​​​.
  
  Essentially, adding a nofollow tag to a link tells the search engines to not follow the link and not pass link equity through that link. It's as if the link doesn't exist from an SEO perspective. In general, most bloggers and online marketers shouldn't have to worry too much about nofollows.
  
  So in your example, WA adds the nofollow to the link in A1 that links to A3 on WB. By doing this, WA can link to WB without passing any value via the link.
  
  1. As mentioned, in this example, the "linker" (WA) sets up the nofollow pointing to the "linkee" (WB).
  
  2. There are a variety of reasons to use nofollows.
  
  Let's say you paid for an advertorial post promoting your business on a top site in your industry because you know it will drive a ton of quality traffic. Technically, since you paid for this placement, you should nofollow any links to your site from this advertorial to stay within Google's guidelines. But many people don't use nofollows in these instances and still get away with it.
  
  In another (admittedly selfish) example, I sometime use nofollows when linking to research on my competitors' sites. This allows me to cite their material without giving them the added SEO benefit that they may otherwise gain from my link.
  
  Or if you have multiple sites that you own and you need to link together, some SEOs may suggest using a nofollow to avoid looking like you are doing something manipulative. When used correctly, you can enhance user experience by linking to relevant content between your sites without looking like a spammy private blog network. Again, some people aren't this careful and still get away with it.
  
  In short, people use nofollows when they want to link but don't want to pass any SEO value via that link for whatever reason.
  
  2b. Nofollows go inside the hyperlink HTML. It looks something like this: <a href="http://www.example.com" rel="nofollow">sample anchor text</a>
  
  3. In my opinion, there is no need to use a nofollow in this scenario. You are legitimately linking to a reputable source in order to give a proper citation. This is the way it should be. No need to get permission, just link away. Give poor Barry his link juice!
  
  However, let's say that you find a perfect example to prove your point but it's on an extremely spammy site. This is where you may choose to use a nofollow tag as a precautionary measure to avoid associating your site with the spammy site. But this rarely comes up because we should avoid linking to spammy sites altogether.
  
  4. I believe you may be referencing the page-level meta robots tag that serves as a nofollow for all outbound links on that page. No, this type of page-level nofollow does not have any direct impact on inbound links. Remember, the nofollow tag affects the "linker's" outbound link so it doesn't provide blanket protection from inbound links.
  
  You may be familiar with this resource already but here is some more info straight from the horse's mouth:
  https://support.google.com/webmasters/answer/96569?hl=en
  
  I hope this helps, Michelle! Good luck!
  
  
• 
  Jose Terrier: Oops. I didn't do so well if I was only supposed to use "the shortest number of words" as +Jim Munro​​ suggested. : )
• 
  Jose Terrier: I'll just leave this here:
  
  http://searchengineland.com/infographic-nofollow-tag-172157
  
  http://www.hobo-web.co.uk/what-is-nofollow/
• 
  Michelle Dear: Thank you so much +Jose Terrier ;. That clears up so much for me! I needed that graphic. One additional question. How would one handle a link to your site from another site that you don't want, but isn't using the nofollow? ;
  
  For example, let's say that a questionable site has linked to your site in an article, and you really don't want value passed to your site from theirs. They haven't used the nofollow tag in their link. Is there a way to handle that directly from your site? Or is there no option besides the domain disavow?
• 
  Jose Terrier: Sure thing, +Michelle Dear​​​​.
  
  If it's one or two links, then I wouldn't really worry about it too much. Just focus on best practices and your good links will typically outweigh a few bad links.
  
  If the link is absolutely toxic or if there are many bad links, then I would suggest reaching out to the site managers asking them to remove the links or add nofollows. Unfortunately, this rarely works - especially if it's a slash and burn splog.
  
  As a second option, use the disavow tool. But please be careful and measured - especially when disavowing domains instead of pages. If it's only a few bad links, then the disavow tool may be overkill.
  
  Third, in extreme cases (like thousands of bad links pointing to a handful of inside pages), I've had limited success letting those "infected" pages 404.
  
  I moved the content to new URLs, taking the opportunity to optimize when rewriting. Then, I deleted the pages with all the bad inbound links and let those URLs 404. They eventually fell out of Google's index and the new pages began to rank, but not as well as the original pages.
  
  But if you're doing all that, then you're probably in a bad place. Link cleanup is not fun.
  
  Keep an eye on your link profile but don't worry about the random dubious link unless it really impacts your rankings.
• 
  Dave Elliott: Jose seems to have everything covered. However, I will add that sometimes no follow links are unintentional. Some cms platforms or certain plugins will make all external links no follow.
• 
  Michelle Dear: Thank you +Jose Terrier ;and +Dave Elliott ;. We were talking about the disavow last week or week before, and now that makes complete sense to me. Dave, I wasn't aware of the CMS issue. I'll be sure to keep an eye out for that;
  
  Again, thanks to everyone for all of your help. Very kind of you.