Software developers generally use one of three ways to alert and deliver version updates to users: a pop-up prompt when you launch the app, a systemwide refresh tool -- like the App Store for the iPhone and Firefox's add-on framework -- or nothing at all (they just hope the user checks their website at some point).
But then there's a fourth option -- one perhaps even worse than the "not tell you" approach. That's the standalone program, installed by a company, that looks for all updates to its suite of software.
We see this only in a few cases, when a development house has the audacity to assume you use so much of its software that you need an entirely separate program just to check for bug fixes. As Google's recent use of this shows, the execution can be anything but sweet.