hybrid
Im a cross of both adults and teens. Am 28, served in the military for 10 years, left the Force, now back in college for my Bachelors. Low income doing serving jobs to supplement subsistence needs.
So as a college "kid", on the "professional" side, I reply to my Prof's mails whilst commuting to sch, listen and watch recorded web casts, reply promptly to emails sent be other students and administrators, upload my lecture notes to read as and when I need to. On the "leisure" side, check out the hot babe from Business Law Module class on facebook, watch crap on You Tube and surf for the latest sports news.
So well, I guess teenagers have their own needs for iPhone to supplement their lifestyle. Everyone will have a purpose for it unless ure the grizzly old man who's still hungover from Nam.