I actually do not see the harm in school students asking for help with homework, as long as they show some effort on their part.
It works a bit like Cboard. Nobody here will write a program for a person, and likewise anyone on yahoo who writes a 2000 word essay for a school student who hasnt even attempted it themselves is rather silly.
You have to show you try before anyone can help, but in some cases, it seems some people will help others online no matter if they show effort or not. Not that there is anything wrong here, its just what happens when the person they helped goes back to school and gets an A? Will they post back and thank them?
