Without meaning to cause offense, if you get paying customers via referals but not via search engines then i'd argue that theres probably issues with your sales copy. It's your job to convince search engine visitors that your service is worth paying for.
HN user
YorkSEO
Yes plenty of companies request linkbuilding only, I'm not going to go into all the details of how we do it, but often its a case of contacting webmasters and asking them to link. Although there are certain techniques we use to increase our success rate which is where marketing aspects come in. In fact most good seo companies are really just online marketers, with seo being an umbrella term for a wide variety of techniques
"Fortunately for me search engines are only a very small %age of my traffic. And no, that does not mean I could be doing a whole lot better if I hired you"
No, but increasing your number of search engine visitors would increase your revenue would it not?
Ok, what about new companies entering a competitive niche? You can have a perfectly optimised website but still not get any traction in the search engines. These days a good cms will do your on page optimisation for you, but links are what you need to make your site visible. Yes you could build links yourself, but it probably isn't the most efficient use of your time as your success rate will usually be lower than that of an experienced seo. And yes I'm a long time lurker who registered just to post this
As an SEO "expert" I take exception to this post, Yes there are a lot of bad companies out there selling snake oil, just like there are in most (all?) industries. That does not mean that all SEO companies are evil and it certainly doesn't mean that all SEO techniques don't work. Lots of people spout the "content is king" mantra, and while i'd agree content is the most important part of a website, you could have the best content in the world, but without SEO, how are people going to find your content and link to it? Unlike the author, most people can't afford to wait 10 years for their site to become popular. The fact is, to get to the top of the results pages you generally need a lot of links, and link building is HARD. This is why every major company has an in house SEO team or hires an agency - because SEO is one of the most effective ways to increase your ROI.