I can’t count how many times I have been contacted to do seo on a performance based term. There are soo many ways that this works against a proper working relationship and clearly demonstrates that those who want this aren’t aware of all that is involved in earning top rankings in Google.
SEO is a multi-pronged strategy that includes the proper coding of the site, and probably an update to the client’s social media assets. In the past it was possible to get a site ranked for long tail terms in a relatively easy manner. One can always go out and get a ton of easy profile links and that might rank well for some sites, but for any term that is competitive or is valuable, getting that top spot will take a tremendous amount of effort to dis-lodge the top site in the serps.
So why should professional seo’s stay away from a performance deal? Think of all the value measured in time, strategy, and execution on your part. All of this that you are giving in exchange for top rankings for stock in some company or however your time would be compensated is a dangerous undertaking.
Even with contracts in place, you must deal with the validation of metrics, confirming your performance, and meeting pre-determined goals.
All of these are easy to skew as to not reward you for your efforts.
There are also the situations where even hitting all the agreed upon goals, sometimes the numbers don’t work out due to the search results not delivering business. These are all real risks that one needs to take into account if you decide to participate in this type of transaction.
So, if you are ever approached by someone to deliver results and get paid only after you have reached those benchmarks, Good luck! You won’t have any competition from me!