Looks more like a sensationalist title than anything else. Without actual hard numbers it really cannot be said that it is selling well. Some company doing a study like this doesn't mean much since you really do not know where the data came from. Not to mention, 7.5% of all activation from Verizon last month sounds really freaking low for a new smartphone that was meant to compete with the iPhone and Galaxy which are probably in the 30%+ ranges at the absolute very least and they say activation for other carriers are in the 0-2 range which sounds bad assuming they mean percent.
(Edit) Android Central has better article where they guesstimate the numbers. Verizon sold roughly 8,000,000 smartphones in Q3 which if we suggested similar numbers for Q4 that means the Pixel has sold 600,000 and we are only one month through the fourth quarter. For comparison I looked back at the Galaxy S6 since I could not find good enough numbers on the S7 and the S6 sold roughly 6,000,000 phones in the first month worldwide. The iPhone 6S sold over 13,000,000 during its first week, but obviously nobody can touch Apple like that.