Do I have a point?

Most of the times that I am in meeting the pressure is to do either of 2 things - talk or keep quiet.

Talk
This is necessary to make sure I maintain an image of authority and facade of contributing to the meeting. But sometimes I wonder am I just making noise or making a point....huh...?

Keep Quiet
This is not advisable most of the time because I will be misjudged as - not contributing to the discussion, not helpful or plain no clue. But I have learnt from a very esteemed boss that the trick is to keep quiet in most of the discussion and speak at the end to sum up or to point out everyones mistakes or oversight and then watch everyone turn envy in green or blush lobster red because suddenly all their talk...bla...bla...bla sounds wasted...and stupid.

Do I have a point? choose wisely when to keep quiet and when to talk... :)