Who Did What? is a recurring competition. It was usually used as the final Power of Veto competition of the season.
The competition was first used during the second part of the Final HoH in Big Brother 4 (US). Eventual Winner Jun Song won over Robert Roman.
The competition was used later on during Big Brother 6 (US). Eventual runner-up Ivette Corredero won the competition, winning her first ever PoV.
The following season, Big Brother All-Stars (US), Janelle Pierzina won the competition, winning her fifth PoV of the season.
The competition reappeared on Big Brother 8 (US), with eventual runner-up Daniele Donato winning the competition. This was her fifth Power of Veto win of the summer.
Reappearing again on Big Brother 9 (US), eventual runner-up Ryan Quicksall won the competition, winning his second Power of Veto.
Reappearing on Big Brother 11 (US) after taking a season off, Kevin Campbell won the competition. This win was his second PoV win of the summer.
The following season, Big Brother 12 (US), eventual winner Hayden Moss won the competition, winning his first ever PoV.
On Big Brother 13 (US), eventual runner-up Porsche Briggs won her second Power of Veto of the season, as she won this competition.
The following season, Big Brother 14 (US), Danielle Murphree won the competition, winning her second PoV of the summer.
Reappearing once again on Big Brother 15 (US), eventual winner Andy Herren won the competition, winning his second Power of Veto of the season.
In the following, Big Brother 16 (US), eventual runner-up Cody Calafiore won the competition, winning his third PoV of the season.
In its next appearance, Big Brother: Over The Top, it appeared as a Do or Die competition. Eventual winner Morgan Willett defeated Justin Duncan and secured a spot in the Final Three.
It appeared once again in Celebrity Big Brother 1 (US), where eventual-runner up Ross Mathews won his third PoV of the season.
It appeared yet again in Big Brother 21 (US), combined with the Billboard Bashers competition, where Jackson Michie won his fourth PoV of the season. It once again appeared as the second part of the Final HoH in which Holly Allen beat Nicole Anthony.
List of Who Did What? Competitions
||Power of Veto
||"Get Your Story Straight"
||Final Head of Household Part 2
||"Who Did What?"
- Jun Song, Hayden Moss, Andy Herren, Morgan Willett, Jackson Michie and Cody Calafiore are the only winners to win this competition.
- In comparison, seven runners-up and three third-place finishers have won the competition.
- Janelle Pierzina, Holly Allen, Nicole Anthony, Cody and Enzo Palumbo are the only houseguests to compete in this competition twice.
- Cody won both times, Janelle and Holly won once, while Nicole and Enzo lost both times.