Exclusive: Facebook Blocked API Access to Ping After Failure to Strike Agreement, So Apple Removed Feature After Launch

It’s not as mysterious as it seems, this mini-controversy about finding friends on Facebook for Apple’s new social music network.

According to sources familiar with Facebook’s platform, the social networking giant essentially denied Apple’s Ping access to application programming interfaces that would allow it to search for an iTunes user’s friends on Facebook who also had signed up for Ping.

Normally, this API access is open and does not require permission.

That is, unless some entity wants to access it a lot. In that case, Facebook claims it requires an agreement for reasons primarily centered on protection of Facebook user data and, of course, infrastructure impact.

With 160 million iTunes users, say sources with knowledge of the Facebook platform, that could potentially mean a lot of impact.

Others disagree, noting the load would be insignificant and it is just used by Facebook to gain leverage from those wanting to access its powerful platform.

That was one of the bones of contention in the talks that sources said Apple (AAPL) and Facebook conducted. The negotiations about an agreement went awry and the pair could not come to terms.

In fact, at the launch event in San Francisco yesterday, Apple CEO Steve Jobs complained to me about what he called “onerous terms” that Facebook had demanded for the friends connection and suggested using search or email to add friends to Ping.

But, at the same event another exec, Worldwide Product Marketing SVP Phil Schiller, said to me in a video interview that one could use Facebook to find friends on Ping.

In fact, Apple still included the ability to find Facebook friends in its demo onstage and also after it made iTunes 10 available for download.

It also currently claims this on its Ping page: “Find even more music fans with a quick search, by sending email invites, or by connecting to your Facebook account.”

But you can’t actually do that on Ping right now.

Sources said Apple went ahead with a plan to access the Facebook APIs freely, but Facebook blocked it since it violated its terms of service.

When that happened, it seems Apple pulled the plug on the connection with Facebook friends.

But maybe not for long. Sources also said the companies were still in discussions about putting the more robust Facebook Connect feature in Ping.

Because, in the end, it is all about connection.

BoomTown has requests into both Facebook and Apple for a comment.

Earlier today, Facebook said:

“Facebook believes in connecting people with their interests and we’ve partnered with innovative developers around the world who share this vision. Facebook and Apple have cooperated successfully in the past to offer people great social experiences and we look forward to doing so in the future.”