Pay Greendimes To Kill Your Junk Mail

After listening to Sara call a half dozen companies this morning to get off their mailing lists (something I greatly appreciate and would never get around to doing), I ran into this post this afternoon:
"Greendimes will remove members from dozens of direct marketing lists and plant a tree on every member?s behalf each month."

I don't know how many people will pay for this service ($3/month). Hopefully a lot. Nice.