“During October, we have seen that search traffic has dropped by more than 1 million referrals on average per week. If this rate of decline continues, current trends would suggest that total DAUqs [or daily active unique users] could fall in Q4, by a low-double-digit percentage from our current base of 130 million DAUqs,” Huffman wrote.

Weird that not allowing people to use your site would lower the number of people using your site.