I keep getting ideas for apps I’d like to see on Apple’s App Store for iPod touch and iPhone. This one may sound a bit weird but I think it could be fun. An app where you can record your mood and optionally broadcast it to friends. It could become rather sophisticated, actually. And I think it can have interesting consequences.

The idea mostly comes from Philippe Lemay, a psychologist friend of mine and fellow PDA fan. Haven’t talked to him in a while but I was just thinking about something he did, a number of years ago (in the mid-1990s). As part of an academic project, Philippe helped develop a PDA-based research program whereby subjects would record different things about their state of mind at intervals during the day. Apart from the neatness of the data gathering technique, this whole concept stayed with me. As a non-psychologist, I personally get the strong impression that recording your moods frequently during the day can actually be a very useful thing to do in terms of mental health.

And I really like the PDA angle. Since I think of the App Store as transforming Apple’s touch devices into full-fledged PDAs, the connection is rather strong between Philippe’s work at that time and the current state of App Store development.

Since that project of Philippe’s, a number of things have been going on which might help refine the “happy meter” concept.

One is that “lifecasting” became rather big, especially among certain groups of Netizens (typically younger people, but also many members of geek culture). Though the lifecasting concept applies mostly to video streams, there are connections with many other trends in online culture. The connection with vidcasting specifically (and podcasting generally) is rather obvious. But there are other connections. For instance, with mo-, photo-, or microblogging. Or even with all the “mood” apps on Facebook.

Speaking of Facebook as a platform, I think it meshes especially well with touch devices.

So, “happy meter” could be part of a broader app which does other things: updating Facebook status, posting tweets, broadcasting location, sending personal blogposts, listing scores in a Brain Age type game, etc.

Yet I think the “happy meter” could be useful on its own, as a way to track your own mood. “Turns out, my mood was improving pretty quickly on that day.” “Sounds like I didn’t let things affect me too much despite all sorts of things I was going through.”

As a mood-tracker, the “happy meter” should be extremely efficient. Because it’s easy, I’m thinking of sliders. One main slider for general mood and different sliders for different moods and emotions. It would also be possible to extend the “entry form” on occasion, when the user wants to record more data about their mental state.

Of course, everything would be save automatically and “sent to the cloud” on occasion. There could be a way to selectively broadcast some slider values. The app could conceivably send reminders to the user to update their mood at regular intervals. It could even serve as a “break reminder” feature. Though there are limitations on OSX iPhone in terms of interapplication communication, it’d be even neater if the app were able to record other things happening on the touch device at the same time, such as music which is playing or some apps which have been used.

Now, very obviously, there are lots of privacy issues involved. But what social networking services have taught us is that users can have pretty sophisticated notions of privacy management, if they’re given the chance. For instance, adept Facebook users may seem to indiscrimately post just about everything about themselves but are often very clear about what they want to “let out,” in context. So, clearly, every type of broadcasting should be controlled by the user. No opt-out here.

I know this all sounds crazy. And it all might be a very bad idea. But the thing about letting my mind wander is that it helps me remain happy.