I realized today that in almost all cases, the sort of ring I want my cell phone to use is related to the ambient noise in the room. If I’m in a quiet place, I want my phone to just vibrate, or ring very very quietly. If I’m in a club or a wedding reception, I not only want it to ring loudly, but I want it to vibrate too in case I can’t hear the ring. Medium noise levels usually call for medium-level rings. You get the idea. The problem is that I rarely remember to change my ring volume when I go from place to place. So I either miss a call because I couldn’t hear the phone ring, or I get embarrassed when it rings in church or something.
The phone could certainly combine this with factors like time of day, ambient light, and other pieces of data to make an even more intelligent decision. For instance, it’s really quiet while I’m sleeping, but it’s also dark and it’s also 3am. So just let me sleep.
Of course, the phone should have a way to change this, customize it, or override it, but I think overall it would be a really useful feature if it was done in an intelligent way.