1. Everyone knows it matters. If you are on the Internet, you realize the power of Google. If you're not listed, you may as well be invisible. SEO is the cure for that invisibility.
2. It has an easy sales pitch. Most SEO firms could have a two word pitch for their services: "rank higher." Getting there may be more complex, but at least describing it is relatively straightforward.
3. Not everyone can do it. For some it may seem easy, but good SEO takes time and attention. Keeping up to date on changes and continual monitoring as well as advanced techniques to impact Google's algorithm make this is a specialty skill most people need help with.
4. Little infrastructure or hard costs. Technically, you don't even need an office space - just a computer, an Internet connection and enough knowledge to succeed.
5. Your clients spend money to avoid spending more money. The alternative to good SEO is paying for search ads. Based on Google's sliding scale auction model, this can add up pretty fast. If you rank highly for the right searches, you can avoid paying the hefty advertising fees to Google.
6. You need to keep it up, you can't cancel. Anyone who has purchased SEO services know that it's a bit like a drug - once you're on it and it's working, you can't go off it. If you do, you'll lose much of the benefit you received while using it.
7. Results are highly visible. The last and perhaps most important reason for SEO's success is that anyone can very quickly see the results. You either rank highly, or you don't.
I'm a believer in the power of SEO services and think they are a necessity for most businesses. Aside from the benefits of doing SEO, it turns out you may be able to learn something from their business model as well.
Rohit is a founding member of the 360 Digital Influence group at Ogilvy, one of the largest agencies in the world. He is author of the best selling new marketing book Personality Not Included, a guide for small business on how to be more authentic, keep your customers and inspire your employees, which has been published globally in 8 languages.