Desirable pero at the rate of smart na P10/30mins of browsing...baka no need.
Pero for globe naman na mahal...there is definitely a need.
The bottom line is HOW MUCH DO YOU TARGET TO SELL THAT APP?
If you sell it cheap you get a lot of clients (including students)... pero not all students needs quick access to their emails. And not all bizmen would really want YM all the time either.
Anyway that is just my opinion....I mean kung mura lang yan I am sure a lot would be interested.