procmail and libnotify: how to display emails received?

I am trying to get procmail to work with libnotify (notify-send). My .procmailrc has a couple of recipes, which just essentially filter mails into different folders.. nothing fancy.

Most of my recipes are like:

:0:
* ^TO_*(address)
FOLDER/

I add the following to my .procmailrc, after all the rules. I copied this recipe from Google. What I want is that on every new mail (before or after processing my other recipes), notify-send command below is run.

:0 ic:
| DISPLAY=:0.0 notify-send "New mail!"

But This doesn't work. What am I doing wrong??