To that end, I wrote an ephemeral messaging system using Sinatra + Redis that authenticates her ID against Facebook and will show her a new message every day. Each message disappears from the public web once its day has passed.
I've released the code on Github; you can use it to display any sequence of messages over time to a set of authorized users. Documentation is pretty sparse right now; I'll be posting better comments, a readme, and license information (using MIT) tonight.
Anyway, enjoy!