One thing you learn in Linux is that no matter how stupid you feel, there are a lot of kindred souls out there. At one time, Google Chrome had a separate update repository. I would regularly get updates. At some point, however, it changed to the main repositories. I didn't get the memo!
So today I was wondering why my version was stuck at 15, when everybody was talking about 23 or 25 (Flash sandbox). I reinstalled it from their web site, and wow, it was at 23! Then I used Synaptic, and it was there! I use Debian.