Before the final logo of Yahoo launched, Marissa Mayer : CEO of Yahoo launched one campaign for 30 day in which everyday new logo was published with the campaign name “30 Days Of Change”.

Here are the all logo from very first day to last day for the 30 days and you can see some variations in logo of Yahoo every day. On the 5th September 2013, New logo of Yahoo was released.

Yahoo! 30 day Logo Campaign
Day 1
Yahoo Day 1 Logo
Day 2
 Yahoo Day 2 Logo
Day 3
 Yahoo Day 3 Logo
Day 4
 Yahoo Day 4 Logo
Day 5
 Yahoo Day 5 Logo
Day 6
 Yahoo Day 6 Logo
Day 7
 Yahoo Day 7 Logo
Day 8
 Yahoo Day 8 Logo
Day 9
 Yahoo Day 9 Logo
Day 10
 Yahoo Day 10 Logo
Day 11
 Yahoo Day 11 Logo
Day 12
 Yahoo Day 12 Logo
Day 13
 Yahoo Day 13 Logo
Day 14
 Yahoo Day 14 Logo
Day 15
 Yahoo Day 15 Logo
Day 16
 Yahoo Day 16 Logo
Day 17
 Yahoo Day 17 Logo
Day 18
 Yahoo Day 18 Logo
Day 19
 Yahoo Day 19 Logo
Day 20
 Yahoo Day 20 Logo
Day 21
 Yahoo Day 21 Logo
Day 22
 Yahoo Day 22 Logo
Day 23
 Yahoo Day 23 Logo
Day 24
 Yahoo Day 24 Logo
Day 25
 Yahoo Day 25 Logo
Day 26
 Yahoo Day 26 Logo
Day 27
 Yahoo Day 27 Logo
Day 28
 Yahoo Day 28 Logo
Day 29
 Yahoo Day 29 Logo
Day 30 : New Logo of Yahoo!
 Yahoo Day 30 Logo