The Power of the Hash # in SEO

by Gary on July 17, 2009 · 21 comments

in SEO

Early this month I promised a post detailing the uses of the # in SEO. Here it is.

As I have mentioned before the hash is often overlooked, if at all used, by SEOs. A very unfortunate thing because it can not only help solve duplicate content issues but help you consolidate the link juice from all the URLs with duplicate content. How is this possible?

According to Randfish’s whiteboard Friday videos “Complex Content Issues” and “Using the Hash” the power of the hash lies in the fact that search engines ignore anything in the URL after the hash sigh. For example if you have a URL such as www.example.com/#10, instead of indexing the contents of this specific URL it will instead point to and index the contents of www.example.com. This is a very useful thing in SEO because this way you can get search engines to ignore pages whose content you don’t want to be indexed such as those with duplicate content. This is especially important if you have massive duplicates because all the links pointing to URLs with hashes will instead pass the link juice to the main URL, which in our case is www.example.com.

As Rand said some applications of the hash include:

  • canonicalization;
  • management of affiliate links; and
  • ability to show limited content.

Of course with every good thing comes a problem. One potential problem with the use of the # is that for single page version of content broken into sections/chapters using the # will result in suceeding sections not being indexed. For example if we have a tutorial on SEO you can expect that it will be long. To make it easy for those that prefer reading the tutorial as a single page we can chop down the tutorial into sections. Hence we can get the following URLs:

www.tutorial.com (This will probably contain the introduction)
www.tutorial.com/#topic1 (will contain the first topic)
www.tutorial.com/#topic2 (will contain the next topic and so on)

As you can see the good thing about this is that link juice from links to the other  sections of the tutorial will instead be passed on to the main URL, www.tutorial.com. The problem with this is that since the search engines will ignore anything after the # it will NOT index the content of all the sections with the hash in their URLs. In essence only the introduction’s content (or whatever is in www.tutorial.com) will be indexed. As Rand pointed out though this shouldn’t be a real problem IF all your target keywords are already found in the introduction, which will of course require conciseness and good keyword selection on your part.

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  • Gry dla Dzieci

    Seems that everything comes with some price. But I have to say that I didn’t know about this # thing, could be very usefull in everyday work with filling page with content. Thank You for this one.

  • Paul

    This is a pretty pointless post. Why not just implement no index, no follow on duplicate pages – avoiding the problems using the hash causes and gaining better control of indexed pages???

    • Gary

      It does not seem “pretty pointless” to the people over here :-)

    • Hannah

      Hi Paul,

      As Gary pointed out the # can be really useful for canonical issues.

      When it comes to using the “no follow” it can actually be harmful in terms of link juice (this is something I plan on writing about in the near future. In the meantime please refer to Eric Enge’s post on SEW: http://searchenginewatch.com/3634387). The # on the other hand is a really good choice because it results in getting all the link juice consolidated (as mentioned in my post). So you see it really is a powerful and not pointless SEO tool. ^_^

  • Adrian

    Good post – thanks for sharing your knowledge!

  • Shareef Defrawi

    Duplicate content is a very real issue and can have serious consequences to your seo campaign. I have been de-indexed for duplicate content before, and believe me, any resolution to the issue is far from pointless.

  • Vaillant Poznan

    This is very good advice. Hash is one of the less known symbols and can be used in so great way. I have not used # ever by building my sites but now I’m pretty sure I will. I wonder if there are some more signs like hash that could be used in some way to increase search engine position?

  • Darron

    This is bad news for whoever doing blog marketing, leaving a useful and responsive comment in the comment area after reading the blog post without spamming is an art, and as reader of this blog, i have to say thanks for this post. Most blogs have a javascript hash trigger or something like that, so to leave a comment, you would have to click


    http://www.phoenixrealm.com/the-power-of-the-hash-in-seo/#Comments

    to leave a comment. And seeing how this page is never indexed by the SE, its pretty pointless for people who pay professionals, to ‘spam’ other people’s blog with the intention of getting a backlink

  • Mike

    Oh my god, I’ve been working as a SEO specialist since 1999 (yeah – it was Altavista, Excite and others then=) but I’ve never used hash ….thanks for the good and wise advice!

    Mike / Toronto Web Design & SEO

  • clems

    I don’t get it.
    Web server aren’t even aware of what’s after the # so they cannot generate different page according to what’s after it.
    The # is only used by the web browser to position the page at the right scrolling position.
    Can you explain that ?

  • Avelina Marshall

    Yes, Same question I asked that how will a server create a page using hash?

  • siya

    Good Post. Thanks for the good and wise advice!

  • Megan Vaillancourt

    Wow! I am going to be singing the hash # all day. I have been working SEO and training on search engine optimization and am embarrassed to say that I had no idea the hash # could be so useful.

    Going to go check it out for a month. Anxious to try this theory

    Megan Vaillancourt

  • Ana Hoffman

    I love finding these little gems that make such a big difference. I am anxious to see # at work.
    Thanks for sharing.

    Ana Hoffman

  • Imran

    i really never thought how duplicate contents can be controlled. There or other techniques as well to control duplicate contents but still, its really hard to change code or tell line by line to google that which page we don’t want to be indexed.

    Your article really helped me a lot. would u imagine i never used # in my links

  • TatvaSoft

    Excellent! Now I can forget about the hassles of redirection and URL rewritings. Using “#” virtually shows has a lot of SEO power in it. Further can be only told of it only after I practice it. Thanks though for this wonderful news.

  • Jane

    I might use hash temporarily only if I had a page under maintenance and to make sure that page will be fixed soon, not for SEO purpose. And if in case I have duplicate content, or any pages that I don’t want to be indexed, I will just delete them. I don’t want to mislead my visitors and I want to aim my objective of having a website, that is, to provide my visitors with helpful information that they need.

  • Scott@ Forex Robot

    I never even knew about the hash until just know. That seems like it could come in handy with doing certain promotions and such.

  • jack

    It seems that everything comes with some price. But I have to say that I didn’t know about this # thing.It could be very useful in daily work with filling page with content. Thank You for the guidance.

  • approachnet

    Never heard of this one before for SEO other then on Twitter. Interesting. I’ll have to try it and see if it helps. Thanks!

  • Megan Vaillancourt

    I tested the hash for over a month. To those questioning this theory, don’t it truly has a benefit

    Thanks for offering such valuable info. Keep it up