Many people don't realize it, but Youtube has some basic analytics for you to track your videos. If you'd like to be able to see who is embedding them and how many plays they've gotten, it's fairly simple utilizing Youtube's Insight tool.
First, login to your Youtube Account and select one of your videos. You'll notice an Insight button on the right sidebar:
Next, select Discovery and you'll find a menu of options:
Select Embedded Player and you'll be met with a list of all the sites the video was embedded on and how many views it received there:
This is a great tool for a marketer! If a site picks up one of your viral videos, this is a great way of tracking not only the sites that are interested – but the sites that are carrying a bit of traffic. You can also download these statistics via a CSV file.