The PHP code checks the QUERY_STRING server variable. If it equals "SoD", it prints "owns you!", otherwise it prints "don't front!". It then shows an example of parsing multiple strings from the QUERY_STRING with explode() and switches. The document describes an affiliate network called Advertgoal that pays on a CPA basis with a $50 minimum payment via PayPal or check every 30 days and offers a 5% referral commission.