I used to see people walking down the street talking on bluetooth headsets all the time. Now, more often than not, they actually are talking to themselves. I live on campus at the UW (Seattle), though, so bt headsets might still be popular with the older crowd (and we might have a higher percentage of people who talk to themselves, dunno).

I believe all the G1's (google phone) show all messages received between Dec 29 and Dec 31 as being from the year 2009.