It's a long-running conspiracy theory in SEO that Google throttles the traffic it sends to sites. Some webmasters have, in the past and up to today, noticed strange patterns with their traffic. Sometime it seems like once they reach a certain number of visitors, incoming traffic vanishes. This has given rise to the idea that Google might be controlling or restricting how much traffic they send to sites listed in SERPs.
Google denies that this happens. John Mueller says that, "...from our point of view that wouldn't make sense." And, personally, I agree. Mueller says that if webmasters are noticing patterns, they're probably organic and have to do with what people search for at different times of the day or days of the week.
Still, just because Google says they don't throttle traffic doesn't mean that people believe them. Opinions are divided on WebmasterWorld. Some members say that they, like myself, can't see the point of Google doing such a thing. Other members say that the data is what it is, and they interpret it as a throttling of traffic.
What do you think?