I have an opportunity to do some pay for performance SEO, i.e. we get commissions on sales we generate. I've previously only done hourly or project-rate SEO work since I wasn't sure how to structure an agreement properly in a pay for performance arrangement. Can anyone give me any tips on how this works, i.e. how do you credit sales to SEO vs. other methods, how can you track exactly what traffic you're referring, etc.? I just want to be sure the deal is fair to both sides.
The only way I have ever seen this really work is if you build another website for the client all together, SEO it and then get paid for the leads/sales that the new site generates.
I know someone who did this for a mortgage broker with a deal that provides this person with a commision on loans closed where the lead is generated from the site, this person did a good job, got ranked very well for local serps where the city name was included in the search plus terms like mortgage, home loan etc and has made a fair chunk of money.
Otherwise, if you are doing pay for performance SEO it should be based on rankings for specific KW's that the customer wants targeted and not on sales.