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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