It's for a limited time and for the UK tickets.
WDW 7 and 14 day 2017 tickets are 25% off for a limited time. It's a saving of £100 per adult ticket. So £300 for a 7 or 14 day adult ticket. 14 day one is always same price as a 7 day one. 25% saving on child (3-9y) tickets too.
Big saving for those who are already looking to go but not got round to getting their tickets yet.
We have ours already as part of our package; just wish Universal had a similar sale on as not got those yet!