What are the advantages and disadvantages of turning NOCOUNT off in SQL server queries?

Question

What are the advantages and disadvantages of turning NOCOUNT off in SQL server queries? ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­

Answer 1

From SQL BOL:

SET NOCOUNT ON prevents the sending of DONE_IN_PROC messages to the client for each statement in a stored procedure. For stored procedures that contain several statements that do not return much actual data, setting SET NOCOUNT to ON can provide a significant performance boost, because network traffic is greatly reduced.

See http://msdn.microsoft.com/en-us/library/ms189837.aspx for more details.
Also, this article on SQLServerCentral is great on this subject:
Performance Effects of NOCOUNT