This growth is very evident on Ancestry as I have tons of new matches. Unfortunately though most of these are not associated with any trees. I think 2018 might even be better.... I ordered five tests over the holidays for my 1st cousins and only two have come in so far. I think a lot of people probably waited until after the holidays to send these tests in and we are just now seeing the increase in processed tests in our own profiles.
I am no statistician, but I'm part pack rat so I checked my "Wiki Genealogy Feed" emails from 13 Jan 2017 to 31 Jan 2017 and found that the addition of the DNA tag to profiles ranged from 0 to 4 (31 total) during that period. During the same period for 2018 however, that range jumped up to 2 to 9 additions (78 total) of the DNA tag every day. I am sure someone can actually figure out the real statistics, but it looks like roughly 2.5 times more added the "DNA" tag to their profiles compared to a year ago. I think that's pretty significant!
So I think not only are people checking their own DNA, they're ordering tests for relatives and friends as gifts. Hopefully a good chunk of those will end up here on WikiTree and GEDMatch as well... I think it's going to be a good year!