Short answer -- Yes. It doesn't matter which question you asked, the answer is yes.

I work for a 'small-ish' Web 2.0 company. My particular application is implemented across a cloud of around 1500 servers (this quarter; more next year, I don't know how many yet -- budgeting is going on now). The Company has other properties (projects) that range in size from two servers to over 10,000, scattered across six continents. (We have clients at McMurdo, just no servers there. Although, that's a thought -- a co-location facility in Antarctica wouldn't have a cooling problem, right? Just pull in the outside air....)

Yes, we do believe in Internet Scale. Any particular web technology from the past fifteen years has been used here, and quite possibly is still in use somewhere in the Production Cloud.

I can't speak for the rest of the Company, but we have been developing a test-bed for our application that uses a combination of WWW:Mechanize, Selenium, Load-Runner (for the few MS-Windows servers), and a lot of home grown code to create a testing/regression-test framework for the Application. This project has been going on for the last three years, and we have around 40% coverage. (That's up from <1% three years ago.)

I suspect the reason you see a dearth of 'real-world problems' on the PM is that by the time a company gets large enough to have to worry about the scaling issue, one of two things happen -- Either they bring talent on board with the experience to sort the problem; or they get acquired by the Google's, Yahoo's, Cisco's, or Microsoft's of the world. These folks have had to solve the Scaling Problem a long time ago (in Internet years), and continue to solve it on a daily basis.