Choosing the right keywords for your optimisation campaign is an important part of the process - after all, it is what will shape the structure and content for most of your site.  There are plenty of tools available to help you research and locate appropriate keywords (although they are all flawed in some way), but the real question is who is more qualified to select keywords for SEO?

Some firms actually abdicate responsibility completely and hand this process over to their client.  In some ways this makes a lot of sense; after all, its the client's business and they should be best qualified to understand what keywords should be targeted to reach those searching for their products or services. This may also be one of the reasons that some companies want to keep their search engine optimisation in house - because no one knows more about their business than they do.

The problem with this line of thought is that everyone with an in-depth knowledge of an industry, service, or product (e.g. clients and in-house departments) suffer from what is known as "The Curse of Knowledge".   Familiarity of industry or specialist terminology and jargon can be blinding when it comes to keyword research and SEO in general.  Terms that are used within an industry are not necessarily the keywords that are used in a search engine by the industry outsider (aka your customer).

There are many examples of this phenomenon.  One of the more well known instances comes from the the travel industry where early search marketing dollars and effort was spent on phrases like "discount airfare" - the accepted industry term.  It turned out that their customers were searching for "cheap flights" - a phrase that was never considered in the initial research.

This is where an external SEO agency with a fresh set of eyes can really help.  By working with its clients and refining a set list of keywords, the agency can get an understanding of the types of phrases that should be targeted but without the distractions that an insider might have.  Are you using phrases in your marketing that make sense to you but may not be in use by your target audience?