I have been researching and will continue to on the subject. There are different opinions and activities depending on goals which is good.
My experience shows that attaching to those doing it well and learning is the best. My tech partners have great ideas we will be trying as we launch new media tools, but I don't know results yet, but willing. In addition to other activity, we will need to track results. This forum has a SEO software that is doing well for the search engines.
My blog is in association with
Know More Media, who has a great strategy and my other sites seem to be benefiting from the two.
To answer your question, I have not hired someone specific to SEO strategy and I know that regardless, I would not have success if not writing and responding to relevant info on the web - organic! This is hard for me because I am not at my computer most of the time like others succeeding in organic strategies. Some people may need to hire writers. That is why being associated to Know More Media helps me...there is always great writing going on in business issues driving traffic to the mother site.