For years, United has been very secretive about how one becomes a Global Services member. My blog entry on Global Services is still the most popular page here, 2 years after it has been written -- accounting for more than 25% of my page hits. It's even the number one search result for "United Global Services" on Google (yeah, I'm proud :-) ).
When I logged into my united account today, I found the following published on the web site:
Ensure your Global Services status for 2009 Fly 50,000 miles on United® or United Express® in First (F, A, P), Business (C, D, Z), or full-fare United Economy® (Y or B) during 2008, and your Global ServicesSM membership will be renewed for the 2009 program year.
Track your progress by visiting united.com/gstracking.
Of course, it's kind of late for the 2009 program year at this point. But still it's now out in the open as to what you need to do to qualify. They even have a web page that you can go to to check your earnings status. Mine is still showing my 2008 earnings (since I know I have absolutely zero earnings in 2009).
Of course, I'm not convinced that this is the only way to get Global Services status. I think that their marketing and business relationship department will use GS stats as a reward for important business partners who bring them substantial corporate business, even if they, themselves, don't fly a lot. That's business as I would expect it to be.