Please note that Link Tracking is currently only available for iTunes based geni.us links.
The iTunes / App Store Affiliate Program have basic tracking capabilities embedded within the program. It's often a good idea to take advantage of the tracking feature anytime you are using an affiliate link.
This tracking can be referred to by a number of names including: user level tracking, Signature Tracking or Enhanced Publisher Interface. It works by letting you add a parameter with a "tag" (up to ~50 URL safe characters) to an affiliate link. The affiliate networks provide the clicks, sales and commissions associated with each of your tracking tags. This is helpful for comparing the effectiveness of different marketing channels (E.g. website vs. in-app cross promotion vs. social), different art (interstitials vs. banner ads vs. 'More' screens), apps (lite vs. paid), or all of the above.
The kicker here is that Apple only back sales at the category level, not the individual item level. This means that you can see how much in sales each tagged link referred, and even media types and prices of the items bought, but you can't see if your app was bought-- or a competitor's similarly priced app.
Tracking geni.us Links
The TRACK Parameter
&TRACK=insertTrackingTag to the end of a geni.us link is all that's needed.
If your tracking tag has any characters that aren't allowed in URLs, you will need to URL encode it. Here is a free URL encoder.
Geni.us Links Built From an Affiliate Link
If your geni.us link is built from an affiliate link that includes a tracking tag from an affiliate network, you don't need to do anything. The Geniuslink service will pass this tracking tag along to each of the affiliate networks to track your link globally.
Choose a Format For Your Tracking Tags
It's a good idea to set up a schema of a few things you'd like to track and separate each keyword by a common delimiter. For example you may want to compare marketing channels by app. To do so, your tracking tags might look like “MarketingChannelName-AppName”. For example: