I like to share some useful information regarding visitor visa for parents.
My Mon applied for regular visa extension last year before Super Visa was announced. Instead of 6 months extension she got 2 years. She went back this year (after year from entry).
Regular extension or Super Visa, both expire once you leave the country.
When she landed again in Canada, CBSA give her remaining time left as visa stamp about till end of 2013, instead of 6 months extension. She never applied for Super Visa, just regular 5 yrs multiple visa 2 yrs back.