Tracking Pinterest pins

I'm not sure that this is possible, but figured I'd ask in case someone who's more knowledgeable can think of a way to do this.

I'd like to be able to know when someone on my site pins something on Pinterest. To be clear, when someone pins something, it pops up a window instead of leaving the site, so it can't track it as an "outgoing link" or something like that. Is there anything I can do?

You can try adding 'onClick' tagging but you will need to dive into the code of the plugin/website for that :)