A. Becoming more computer-literate and going straight to sites as opposed to always Googling it before clicking, even once familiar with the URL, which won't correlate to usage
B. Visiting the site enough for AutoFill to take effect, which is ever-so-slightly inverse in correlation in terms of search popularity to site popularity
Here's a FB-related search term people will still use, even with AutoFill for Facebook, as some evidence. The rise is a similar pattern, but lacking the major drop: https://trends.google.com/trends/explore?date=all&q=Facebook...