Does Raspberry PI Model B+ Works Over 24*7 and 365 days continuously??
There is a thread discussing the issue for the older types of RPi (not B+) Is the Raspberry Pi suitable for running continuously, 24/7?
But given the changes in the design (switching power regulators and lower power consumption) I do not see why it should not be running 24/7. As long as you're not proposing an application putting lifes or health at risk you'd be fine.
Since the new design is from July this year you'll probably not getting the answer that anybody has been running one for a year already...