Google's Social Graph API and privacy

In light of recent discussions, especially the ones at the latest BarCamp, on Anaj’s blog or in Christian’s posting on , I think these quotes from a Compiler entry on Google’s new Social Graph API are interesting:

There is also the problem of privacy. While the new API is using only publicly available data, that won’t stop some from finding it invasive. Despite the fact that most sites using XFN or FOAF markup wear it like a badge on their sleeve, most users remain unaware that this code is in their profile pages.

And this one here:

But the problem isn’t really Google’s new API, nor is it the underlying XFN and FOAF markup.

The problem is that there simply isn’t a privacy mechanism that works throughout the web and that remains, if not a stumbling block, at least something that will bother many users.

While the above quotes refer mainly to the handling of XFN and FOAF markup, it holds true for the usage of APIs in general. By not having some sort of privacy regulation in effect, people will quit signing up for services of which they can’t be sure whether their data is going to stay safe inside or not.