I have the impression that there is a big group of voters who like to see some changes in their favourite programme. Let me come up with an example:

SPG won almost everything until 2005 and almost nothing in 2006. The main “change” in SPG was a slowdown in targeted promotions. PC was next to nothing until 2005 and won big in 2006. The main “change” in PC was the possibility to enrol in a lot of targeted promotions for everyone and referrals for “Royal Ambassador”. It would not a big surprise if PC will slow down as these freebies are too costly. I guess voting will go down the hill.