How and when to remind yourself to remember stuff so that you won't forget

Excerpted from the really cool article from wired about Supermemo.

Was just talking with Dan from fliggo.com and he mentioned this should be the way startups should message users so that they don't forget about the services they try. Hmm... very interesting.

Aside from that, this chart appears to have very broad application for anyone who has to learn new stuff. Which should be you, right?