Here is what the changelog post looked like 16 days ago. I took this screenshot from an archive.is snapshot.

Here is what the changelog post looks now. #5, 6 and 7 were added and the post was edited 11 hours ago! #6 is especially disconcerting:

More tailored "defaults": a small percentage of logged-out users will, after browsing the site for a bit, find that their "default" frontpage includes a more tailored set of subreddits based on their browsing habits

Looking through the comments only one person mentions #6, and that was a day ago. This leads me to believe that the addition of #6 was very recent, within the last few days.

So we now know reddit tracks you even if you're logged out. And I'm willing to bet they're testing this technology to manipulate the front page of non-registered users who make up 90% of redditors. Want hillary subreddits to appear on the front page for 90% of reddit users? No problem, it's now a button click away.