Ping.fm works but I can't figure out how!!

This is going to sound really dumb.

I set up my ping.fm account a while ago to announce any of my blog posts.

Now, I cannot figure out how ping.fm is getting notified of my blog posts. I was thinking it might be feedburner but I don't see how I would have set that up.

I have a wordpress blog and have a plugin to connect with my feedburner feed. Thats it. I don't have a plugin for ping.fm or anything.

Is there a way for the ping.fm team to actually look and see where the feed is coming from?