This article isn't really saying anything. It's just saying that a lot of people feel like the job market has gotten tougher, but we don't have any solid evidence to prove that.
Personally, I recently got a new software development job, and it was offered to me from the very first company I interviewed for. (This is out of the ordinary for me, as during past job searches it took me several interviews before I got an offer.) Did I get a job quickly this time because the job market is better, because I've become a better candidate, or because I got lucky? It's impossible to say. Anecdotal evidence doesn't really mean anything when it comes to market competitiveness IMO.
So to clarify, this is saying that if you're logged into your Google account in Chrome and you launch an incognito window, your browsing activity will still get associated with your Google account, which will affect your ad recommendations? Is that right?