Upvote:2
The 2 year provision is only for the initial visit. Once you exit your visa is still valid, but you can stay for up to 6 months on each visit.
The Super Visa is a multi-entry visa that provides multiple entries for a period up to 10 years. The key difference is that the Super Visa allows an individual to stay for up to two years on initial entry into Canada, while a 10-year multiple entry visa would only have a status period for each entry of six months only.
From: http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=426&top=16