How do I automatic daily messages for first 30 days?

[jackzliu]

I was reading this about how to get a new user hooked:
http://www.feverbee.com/2008/10/keep...r-21-days.html

So I was thinking of creating 21 different "tasks" that a new member can do when they log in for their first 21 visits. I envision something like a one or two line message either going their email, or private message that tells them to do x.

These messages would be automated for every new person that joins.
The messages would only show for each day, not all at once.

Has anyone done this or attempted to? Obviously, I know I can always just setup a "What to do page" and list what to do for the first 21 days but I think it's cooler if the member gets a reminder each day.