Had a few problems trying to find out if my page was in a postback or callback.  I only wanted to log the traffic going to the page on full page views, not on partial rendered callbacks.

I tried the IsPostback and IsCallback but they did not give me the answer.  Finally, after some digging, I found the:

ScriptManager.GetCurrent(Page).IsInAsyncPostBack

That will tell you if a partial page render is the source of the page call.