The last "study" I heard of was when Mythbusters put toothbrushes all over the house and tested them for fecal coliform bacteria
I like the mythbusters and what they represent and how they expose people to the scientific method, but most of the time what they're doing isn't science, and there's a reason why they are blowing stuff up every other episode.

People do stuff, like washing their hands then flushing the toilet, and then they're spreading it everywhere. We are dirty talking monkeys; at least all racoons wash their hands before they eat!
I mean, yeah, they're right next to the dirty part, but there's really never any contact, there. I'd totally eat off the toilet seat (my own, of course, not a public toilet) before I'd eat off the kitchen floor, for example.
There's a plume 10" tall generated when the toilet is flushed if the lid isn't down, that yes starts drifting everywhere... usually right near where a toilet paper roll is. The droplets end up being so fine that if you flush and leave and someone comes in and uses it soon after, it still just all floats up anyways and your only option is renter's insurance & lighter fluid. It's unlikely to mess with you if you have good hygeine, and it's easier for some people to ignore than others.
And yes, toilet seats are surprisingly low in bacteria due to their surface type and their lower moisture, and you generally have more bacteria on your face than your bum cheeks for the same reason.

The message is that it is lower, because it has a harder time reproducing on it due to the lack of water -- it still gets deposited.
A few links:
Research from Dr. Charles Gerba Finds Average Toilet Paper & Towel Dispensers Have More Bacteria Than Average Toilet Seat
Flushing Lidless Toilet Sends Spray Of ........-Causing Bacteria Into The Air: Study
And now I must go strip naked to slather myself in disinfectant and think happy thoughts.