Tracking When a Document Is Opened

I share a lot of documents in form of PPTs, PDFs, and Word documents.

I would like to track (and ideally be notified via email/sms) when someone opens one of my documents that I share.

Is there a good way to accomplish this via code (maybe embedded within each document), but if there's a more general purpose way, even better!

My code of choice is python, but I'm open to another language if it accomplishes this task.

PS. Sorry guys, I realize that I posted this in the wrong section, so hopefully it'll be moved over to the Forums section. But since this post is currently in the How-To section, I'd like to post this URL that I've found helpful, which shows how to discover and also embed objects within a PDF file: http://blog.didierstevens.com/programs/pdf-tools/

Thanks!