Here is the perception I am left with. If you can not make any kind of guarantee then I feel as if your biggest marketing effort has been on yourself and not your customers. You are selling your services, selling your reports, selling yourselves, etc. However, you are not working hard enough to do the job your customer hired you to do.
If you can not guarantee an increase in search engine visibility, how about guaranteeing an increase in search engine traffic? How about an increase in online sales? How about something as bold as a 10:1 return on your customer’s investment? My point is that there are several metrics that can be reported on and that could be used to back a guarantee. If you are unwilling to offer some kind of guarantee, I question your ability to perform.
So what do the service providers say?

The above statement came directly from Google. It was sent to me by a service provider I spoke with and challenged them when they said they would not provide any kind of guarantee. They copied my boss on the email as well as everyone they knew at the company I work for. They really hung on the “unethical” word. My response is, “So?” Let me be clear, I am not saying use “unethical” practices. I am saying if Google says the company is using unethical techniques and/or misrepresenting their abilities if they are guaranteeing search engine ranking, then find another metric to guarantee that is not considered unethical. Search engine traffic, sales, something.
Search engines & techniques change, so should you.
Let me touch on another part of the statement from Google. They say, “It is simply impossible to guarantee what an unrelated third party, like Google, is going to do.” I understand that, but isn’t it also the responsibility of a company that is paid to provide a service like search engine optimization to be on top of what a third party like Google is doing? If Google is changing their algorithms, shouldn’t a company that says they specialize in search engine optimization know about it and have a strategy to address it?
The internet is always changing. The search engines are always changing. I would expect a company that provides services that are so closely tied to these companies, their practices and their technologies to know as much as possible about what changes are being made as well as what changes are being considered in the future.
The idea that Google, Yahoo, MSN and all the rest of the search engines are always changing what they are doing and the techniques/logic they use to produce results is not an acceptable excuse for not giving some sort of guarantee.
Still, no guarantee.
You have the right to not offer a guarantee. I have the right to choose another company as my service provider.