What is meant by 'informal organisation?

What is meant by 'informal organisation? State any three advantages and any two disadvantages of
this form of organisation.
State any two advantages and two limitations of informal organisation.
Explain formal organisation and informal organisation. Inspite of many disadvantages, why is existence of ‘informal organisation’ important? Give any three reasons.

Formal organisation It is a system of well-defined jobs, each bearing a definite measure of authority, accountability and responsibility.
Informal organisation It is a network of social and personal relationships, which originates spontaneously as a result of interaction amongst people at work
Advantages and disadvantages of informal organisation :
Informal organisation has the following advantages :
(i) Prescribed lines of communication are not followed. Thus, it facilitates quick feedback and spreads information faster.
(ii) It provides a sense of belongingness and gives due respect to social and psychological needs.
(iii) It provides the necessary environment for individual creativity and innovation.
(iv) It contributes to fulfilment of goals, promoting the feeling of cooperation among employees.
Informal organisation has the following disadvantages :
(i) Informal organisation structure spreads rumours.
(ii) It opposes the policies and changes of management.
(iii) It generally prefers status quo and existing work routine.
(iv) It gives importance to individual interest as compared to organisational interest.
(v) It pressurises members to conform to group expectations.