channel
data1
data2
These parameters are recognized from Replicated site URL, and are added to click tracking code. Example:
http://examplesite.com/sites/testaff/repl.html?channel=mychannel&data1=customdata1&data2=customdata2
This URL will create click, which belongs to affiliate 'testaff',and will have channel, data1 and data2 set.