What Happens When SEO Stops?
Some website owners, both big a small, still have the perception that SEO is a one-shot deal. You put in a few months of work and then move on to some other project. While it's true that increases in traffic can be had with just several months work, growth will stop shortly after the SEO efforts stop. Of course your first inclination will be to dismiss my assertion because it's self-serving. After all, if SEO was a one-time event, I'd be out of work in short order. The problem is that I can't prove to you what happens when SEO activities end so instead I'll have to settle for describing 3 areas that you can hopefully related to.
Re-Designs Need to be Monitored
By far the biggest problem I've seen with not having an search engine optimizer constantly monitor a website comes from re-designs. With re-designs the business owners are more concerned with describing their vision to the graphic designers who are in turn focused on translated the vision in to a visual representation. Coders and developers, who are often given unreasonable deadlines, do everything they can to turn the visual representation in to HTML for delivery to web browsers. Guess what? Under such situations a 2-year SEO effort costing hundreds of thousands of dollars can easily be derailed because no one is making sure all the best practices are being applied.
Changes in the Search Engine Industry
The search engines, Google in particular, are constantly improving their ranking algorithms. These improvements are partly inspired by those that have exploited flaws and partly inspired by a desire to improve users' search experience. Not to mention that a company that doesn't change is one that will be demolished by its competitors and so Google puts a lot of resources behind staying ahead of Yahoo and MSN. All of these improvements and changes mean that what once ranked #1 could now fall to the second page. And the tactics that were used to get that #1 ranking are no longer sufficient.
Changes in the Competitive Landscape
If you kept your money under your mattress instead of investing it, you might feel that it's safe. But what you'd be forgetting is that over time you will effectively lose money due to inflation. The dollar you have today buys less tomorrow. Competitors on the web are a lot like inflation. You need to keep up with the competition just to retain the same level of traffic you have today. Reaching a certain traffic level with your website and then halting all efforts will ultimately result in you losing traffic over time. An on-going SEO effort will include doing the necessary tasks to remain competitive with other similar sites in addition to pulling ahead of them.
Fortunately for me, I don't need all website owners to believe me. Those that don't will let their sites languish which will just make it easier for me to leapfrog them when their competitors enlist my SEO services. I have to admit that it's nice being in this industry!