First, the advantages for people were already described. Scribd provided them with things that they found valuable. You dismissed these things because they weren't valuable for you. When you say:
> I'm still curious to learn about the advantages of scibd.
You really mean "I'm still curious to learn about the advantages of scibd for me." If you meant what you originally said, your being purposefully obtuse.
Indeed, in rereading you original comment, you were simply dismissive, and all the alternatives you provided lacked the specific feature sets he was looking for.
> With enough ideas or usage scenarios, maybe somebody will make something better!
Yeah, another document host. Scribd2.