Do you agree that Internet is the major cause of productivity drain at workplaces as employees spend more time on web-surfing (not work related)?

I don't think that internet is a cause of productivity drain for a good employee. If you have a bad employee then he will take even his fellow employees a reason for wasting time in poor gossip. Internet is a source of being updated about any new topic and its a must for any work. The only thing is how to use internet. I think if proper amount of work is given to someone with proper guidance about the outcome then nothing will impact on a working nature of an employee.

Never. Internet came in the90's, if it is the sourse of productivity drain than all the theories of motivation, two factor theories, research on organizational behavior before the internet were not necessary. It is said that human beings by nature avoid work. Therefore we can not blame internet for that.