Another way to find this information is to do a simple Google search. For example, one could place the following phrase into Google Search:  “(product name) + affiliate program”. (Replace “product name” with the name of the product you are promoting.) There is an interesting chrome addon called Affilitizer is available which makes this process easy.
Some advertisers offer multi-tier programs that distribute commission into a hierarchical referral network of sign-ups and sub-partners. In practical terms, publisher "A" signs up to the program with an advertiser and gets rewarded for the agreed activity conducted by a referred visitor. If publisher "A" attracts publishers "B" and "C" to sign up for the same program using his sign-up code, all future activities performed by publishers "B" and "C" will result in additional commission (at a lower rate) for publisher "A".