A Forum post by Blizzard designer Travis Day announces that they have heard the clamor, and have decided to make the anniversary buff to the legendary drop rate in Diablo III permanent going forward, instead of reverting to the previous drop rate today as was planned. The double drop-rate for Rift Fragments, however, has just ended as planned. Here's word:

I come bearing exciting news. Due to the overwhelming popularity of our Anniversary buff we have decided to keep the increased Legendary drop rate once the Anniversary celebration ends. Once the buff is disabled tomorrow morning, you will find that the new base line drop rates for Legendary items will be the same as those you have all enjoyed for the last week.