This seems to be geared towards developers, my summary is: steam was previously telling developers people received notification of their game being on sale because it was on somebody's wishlist and it went on sale, however if the person who wish listed the game had more than 25 games on their wishlist go on sale at the same time they would have not actually received an email notification.

This feels like it will not affect end users in the slightest.

Where's the April fools?