Its the viewers choice, you probably weren't ther to read the amount of messages tht the survey got.
The public did vote for big b being the most overrated, don't blam it on rediff, see all the comments and you'll see big b and srk have the most votes for being overrated along w.other actors/actress as rediff mentioned.
But, they got rajinikanth, salman khan wrong since both these stars did alot of votes as compared to other people for being overrated. Hrithik roshan got a little bit more votes thn those too.
Now ajay devgan ws never mentioned in all the comments as being overrated, i don't why rediff placed him on the overrated list.
