Since now I was very rarely contacted by clients that found me from my website, and consider that I am online with my website since 1996, each 1-2 years I renewed it making it tecnically and graphically up to date (being a web developer and designer, it should be an example of good design and efficiency), it responds well to keywords and have a good number of visits (thinking locally), even if my goal is not to have a huge amount of visitors. In fact I use my website as a portfolio to show to existing and potential clients example of my works, skills and competencies.
I always found new works to do by word of mouth by other clients, after the first times that I built a stable clients base, I was then always contacted (more or less frequently) by people who heard about me by other satisfied clients.
I would not base my business on the fact that I should be found on line for searches like "web developmemt company" because (right now) it outputs 71.900.000 results, and you will be one on 71.900.000, there is a very far chance that someone will contact you by that method, unless you will optimize the site to be found in your area, and even when you will succeed in that, it will also depends on how many other similar companies you have around, for example I am not a in big city and I have around 8 web companies within a 5km of radius, and other 30 (with some of them important web agencies) within a 25km of radius from me.
In my opinion, to find a stable base of clients is more important to be known in your area as a reliable professionist that people can trust, rather than spend weeks of work in writing blogs etc to make traffic and then play dog eat dog game in the search engines results and rankings.
By the way to have a simple good looking, efficient, up to date website with portfolio, CV and other useful info, is a must.