I was pleasantly surprised to find recently that TransLink's Journey Planner has been updated to include Google Maps integration, so you can see exactly where your journey will go. That's incredibly useful, especially when searching for a bus stop on an unfamiliar route - a problem I have had many times on Brisbane's public transport services. I imagine from there it's a relatively simple step to allowing Google to present that public transport information directly on the Google Maps website, but frankly that doesn't seem necessary when the Translink service is quite good enough, as long as you know where to look for it.
Mokalus of Borg
PS - It also provides "just walk" as a journey option if your departure and destination points are close together.
PPS - It never used to do that.