no I mean if someone only visits facebook or some other social networking site then they'll be happy with this speed. I know many guys use mobile for social networking site. and these plans r atleast better from mobile surfing

these plans are not for downloading purpose or for streaming videos. the basis of these plans only to attract these kind of customers, who wants limited bill with unlimited surfing.
You do realize that everything you do on the Internet involves downloading data, right?

Anyway, let’s not kid ourselves: the point of these plans is to squeeze money out of people who don’t know that better options exist, and who think that Internet access is supposed to be limited.