Koum wrote (unedited):
WhatsApp crossed 1B Android downloads. btw our android team is four people + Brian. very small team, very big impact.
The “Brian” presumably refers to WhatsApp co-founder and vice president Brian Acton.
The milestone announced by Koum follows two key events for WhatsApp in January: WhatsApp via the Web launched for Android users, and WhatsApp topped the 700 million monthly-active-user mark, saying that 30 billion messages were being sent daily.
Readers: What’s next for WhatsApp?