From my personal experience I do know these 2 countries share info on immigrants. In my case it helped me establish my case rather than jeopardize it. Canada Immigration did ran a check list of info on me with the US Immigration. Canada Immigration acknowledged that it had done so shortly before my case was settled.

As far how it is going to affect you depends upon what is the intent behind entering Canada.

Under a new agreement far more details about the identity, nationality, criminality, travel and immigration history of immigrants and visitors can be shared between the US and Canada.

http://www.nationalpost.com/news/story.html?id=2261647&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+NP_Top_Stories+%28National+Post+-+Top+Stories%29