Net neutrality is the principle that Internet Service Providers and government regulating the internet should enable access to all content and applications regardless of the source, and without favoring or blocking products or websites. The act of promoting and advertising of any website by the ISP is considered as favoritism which hinders the development of other such websites. These types of favoritism do not maintain equal opportunities to all the sites or components of the internet which are basically against the principle of net neutrality.
Net neutrality is bad for ISPs as well who want to leverage their position as network providers to give their own services special treatment and thereby make more profit. It is also bad for end-users who want to exploit those leverages instead of using the services as per their handiness. But, in the context of fairness, it is good because the internet without neutrality has a very high potential for abuse and inequality among web services.
Ncell announced a new scheme to offer free Facebook which violates the principle of net neutrality. These propositions certainly are very appealing and beneficial for those who only wish to use these sites for their respective purposes. But, on the other hand, the scheme is a disadvantage to other sites. With free Facebook, only a few percent of the users would opt to try any other site. So, what it does is obstructs or bias the views of the users as anyone would find it apt to use the free site.
So, net neutrality, which in a sense maintains impartiality among the web services, is violated by Ncell. It is an unethical act and should not be given any more encouragement.