More details on the short-lived iTunes Ping/Facebook integration. Also see this GigaOm post for a reality check on the complementor/competitor continuum in this context.
The word is that Facebook may have pulled the plug on the Ping integration at the last minute.
AllThingsD hears from unnamed sources that Facebook blocked Apple's use of the Facebook API within Ping "since it violated its terms of service." As a result, Apple reportedly then killed the advertised find-Ping-friends-via-Facebook feature.
Facebook's API is generally open for anyone to use, but there are a few rules. The company's developer agreement states that if an application exceeds more than 100 million API calls per day, "please contact us as you may be subject to additional terms." Apple says there are 160 million iTunes customers--and therefore potential users of Ping.
It seems those "additional terms"--whatever they were--are the "onerous" ones Jobs referred to.