By this I mean, if you leave it plugged in all day while listening to internet radio, will this hurt the battery? I see that Apple does not suggest leaving a Macbook plugged in all day. So, if they have the same types of batteries, wouldn't it be the same for an iPhone?
In neither case, the iPhone or the MacBook, will leaving it plugged in hurt the battery and it cannot be overcharged. What they recommend is doing one complete power cycle per month for exercise, the lithium polymer batteries need this.