And not per se new. I imagine most people don't do it, but I (and I'm sure plenty of others here) have been logging all of my IMs, emails, etc. for at least the past 10 years.
Truth be told, it isn't that useful.
The iPhone logs all my texts. I've had an iPhone longer than I've been dating my current girlfriend (dating over 3 years now), and it's a little fun to scroll all the way back to the beginning. :)
