The term ‘leakage’ refers to an instance where an affiliate may potentially lose commission due to an untracked action on an advertiser's website. For example, displaying a telephone number can result in the sale being completed offline and unless you have a call tracking solution in place, the sale would not be tracked and the publisher would therefore not be rewarded for their efforts.
Where possible either integrate a call tracking solution such as having a caller quote an affiliate ID as a reference, or use a technical solution to avoid displaying your telephone number to incoming affiliate traffic.
The simplest way to remove leakage is by moving any points of leakage to less prominent places on your website. For telephone numbers it is also common to move them to the bottom of the page or into the ‘Contact Us’ section of your website.
Third-party banners and any other forms of advertising that link to other sites or interfere with the customer journey should also be avoided. An offline promotion that can’t be tracked back to the affiliate is another form of leakage that should be considered.