In reply to a post by Chrysalis:

then you dont have worries about sky shifting platforms again (to me thats stupid)

Stupid for customers, profitable for Sky. Moving their email platform from ad-free Google to ad-supported Yahoo will save Sky a lot of money (not that they are poor).

9 out of 10 email users do not care who provides their email once they pick the username that they want to stick with. (well that's my assumption that may be wrong).

For the other 1 out of 10, 95% will complain but do nothing, the remainder may complain further but again may do nothing or may possibly move as you suggest.