Can External Links In Comments Hurt Your Google Rankings?

I was asked an excellent question today in my post from last week on white hat link building. The question, from Irina Wiedemann, asked: –

Hey David,

thank you for the article, it was exactly the information I needed! But I still have a question left… I’m a newbie to “the online business / blogging / SEO world”, so please don’t laugh :)

Ok, can comment links (urls linked to the name of the person who left a comment on my blog) harm the rank of my site if the site of that person contains black hat SEO?

Because I heard that enough links from spammy or suspicious websites can get rapidly a website down, even if this is a high quality site (due to Penguin 2.0 I guess).

Thank you for your answer in advance!

My first thought was assuming you have the rel=nofollow attribute added to comment links, then no. The rel=nofollow attribute was originally designed to tell google ‘I cannot vouch for the quality of this link’ – it’s a bit like saying ‘it ain’t my fault what they’re up to guv!’. I am sure you are also aware that nofollowed links do not pass pagerank or do anything directly to improve the linkees search rankings.

But then I started to think about it…

Would an excessive number of nofollow links to bad neighborhoods potentially cause a red flag, or at least trigger google to take a closer look at your site?

And what is an excessive number of bad links anyway? 10, 20, 200, 2000?

If a large percentage of your comments were linking out to unrelated sites could this potentially cause theming and relevance problems?

Clearly this was something I had to look into in more detail.

I turned to google and did some searching for what other people thought about the matter. Unfortunately there didn’t appear to be any concrete school of thought and in fact, it was very difficult to find any opinion. There was a lot of the usual stuff about linking out to bad neighborhoods etc, but this was mainly relating to ‘dofollow’ comments.

So, in the absence of any clear guidelines, I think it is best to be mildly cautious and I would advise the following as best practice when dealing with external links in blog comments.

1) Always set your blog up to require moderation on comments (apart from trusted users)

2) Always have rel=nofollow, certainly for new commentators

3) If the name of the commentator is ‘my keywords’ then I would suggest declining it

4) If the url looks suspicious, check it out before approving. If the comment is good, but the website looks dodgy, approve the comment, but remove the link. You might want to drop an email to the commentator to explain why.

Comments are the lifeblood of blogs and a good comment deserves a link (for traffic, not for ranking juice), but if you feel something is not quite right, then it’s probably best not to approve it. As I mentioned above, even if your site is not penalised directly, it might cause a manual review and this is something you (probably) don’t want.

One final comment (on comments). If your blog runs on wordpress, you might want to install the broken link checker plugin, which will scan for broken links on your site, inlcuding comments. This will be particularly relevant if your site has been around for a while. Broken links are never good for your site’s SEO.

So, what do you think? Can nofollow external links in comments potentially hurt your site? Do you agree with my advice on best practice?

Thanks again to Irina for the great question and eh… feel free to leave a comment!


About the Author

I'm a web developer, programmer, blogger and SEO expert from Glasgow, Scotland, with over 15 years experience in the industry. When I'm not writing about marketing and SEO you'll find me strumming the guitar in my band or listening to Revolver on repeat. Follow me on twitter, connect with me on google+ and add us on facebook to keep up with all the latest trends in SEO and online marketing.

Stephen Kenwright - July 24, 2013

Nice David, and I agree that a good comment deserves a link…but with rel=”nofollow” attached. It’s unsolicited…you’re asking for opinions, not opening your site to become an advertiser.

This was big earlier this year: – it was penalised for being excessive, but you don’t want to risk your site for the sake of a little insight. If you like someone’s thoughts, maybe write about them later and link that way. What do you think?

    David McSweeney - August 7, 2013

    Thanks for the link Stephen, that answers a few questions. I completely agree that comments are a great way to find ideas for new posts (and share the link love for the commenter) – answering questions is what it’s all about, particularly if no one has answered them before. Answer the right question and you’re also likely to pull in some nice links.

Bernard Z. - July 24, 2013

Hmm… I never thought about it to tough really. The way I look at it as long as it’s relevant it’s safe. And comments can also drive traffic if its a good enough comment. I think only good can come out of it, assuming that a good comment is linking to a good blog, and also placed on a good blog.

What do you make of a comment that’s bringing you visits?

Tom Jamieson - August 4, 2013

Hi David,
Certainly something to think about, and obviously not much information on it at this time. I use CommentLuv on my site, which requires initial moderation of all comments. I only approve comments that are from known sources, provide value, and are relevant. I visit a site that is linked to a comment if I’m not familiar with the source. While you want good traffic, engagement, and relationships, you can’t sacrifice your good name in the process.

Scott Craighead - August 5, 2013

David, I think if you spend your time worrying about commenting on this or on that site. Your going to force yourself into a bad practice. I comment on low or high, heck, I don’t even measure them. I comment because I want to and that’s how everyone should be. If Google decides to penalize me for this. Well then they are just going to have to penalize me. – Scott Criaghead (p.s. You should get comment-luv premium)

    David McSweeney - August 7, 2013

    ah, maybe slight confusion. I was talking about comments placed on your blog and whether this could potentially cause a problem.

Apollo - August 7, 2013

I always moderate my comments and I agree that if their Name are keywords it is better to delete them. I do think some worry a bit too much about pleasing Google and while it is important for traffic no doubt it can also alienate others. I try to find a good balance.

Prakash - August 7, 2013

Google sending a dubious message again. Now, people need to figure out:
– what links will be ignored and what links won’t
– if a linking site is deindexed does it mean links from it are ignored or does it ean these are the links that will hurt you
– if you disavow a link that is ignored, what happens then
– what actually works as supposed at Google and what’s broken

Very misleading, as usual.

Sagar nandwani - August 7, 2013

After penguin update it has become first priority for search engine to develop a functionality like webmaster have control to remove a suspicious in-bound link, as I personally interested in such tool, using this tool, it may that link remains same but there isn’t any effect of such link to ranking.

hiren - August 7, 2013

till now i thinks that it done not hurt us… thanks 4 realize it…

zaveethaslam - August 7, 2013

Absolutely not, it increases the confidence about your website and improves your page status 😛

Sarmista Aun - August 8, 2013

I do agree with you. It is always better to avoid those type of comments where will get keywords instead of commentator’s name. It may be considered as spam.

Denis D. - September 30, 2013

From everything that I know and all of the research that I have done so far an external nofollow link can not hurt your site. If I can also add one suggestion here, you should make all of your affiliate marketing links nofollow because the dofllow links lower your page rankings. This tip I learned from Pat Flynn at Smart Passive Income. Pat has a ton of affiliate marketing links and if they were all dofollow then it would really hurt his site. Additionally using pretty link to make your links simpler and shorter, and also to keep track of who clicks on what is a good idea.

    David McSweeney - September 30, 2013

    With regards to affiliate links, you are correct that they should be nofollowed. As you receive remuneration when a customer purchases it can be classed as a paid link of sorts and therefore according to google TOS should not pass pagerank.

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