The article says Twitter saw a lot more retweeting after implementing the button. (“After the retweet button debuted, Wetherell was struck by how effectively it

The article says Twitter saw a lot more retweeting after implementing the button. (“After the retweet button debuted, Wetherell was struck by how effectively it spread information. “It did a lot of what it was designed to do,” he said. “It had a force multiplier that other things didn’t have.”) It seems like they saw an immediate change in behavior and results, enough to conclude the button directly affected behavior. My anecdotal experience was similar. Though I agree we will never know how effective would have been the third party tools or how much the delay in third-vs-first-party development would have affected Twitter’s growth.