Whenever you post, make sure you do not tick the "Track this thread and email me when there are updates". That option is just below each typing box where you type your message.
The 2nd way is to untrack individual threads that you are already tracking. To do that, click the "My Tracked Discussions" option in the left hand column, right up the top.
In the new window you will see a list of the discussions you are currently tracking. You can either untrack individual threads, or tick the top empty box, (next to "Topic"), to select them all. Then click Unsubscribe. I am unsure if the 'select all' button works for all of the entries in the whole list, or just for each page.
Hope that helps.
Mark
Is there any way to change my CNET alert notifications so that I do NOT receive an email when *I* post a reply to a forum post I am tracking?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic