Users need to activate the affiliate links themselves by clicking on a modal that appears when an affiliated website is visited (indeed by insertion in the page's html content). The majority of the fee goes into tree planting.
How large is your fee/overhead? Are you changing page content/high jack affiliate links, or are you only adding tracking parameters to type-ins/bookmarks?
yes, I'm interested in the overhead as well, and how much of that is actually going to planting trees?
The only information on the site about this question would be; "We use the majority of that fee for planting trees."