Several social media best practices - particularly on Facebook - come from big consumer brands: Dunkin Donuts, Starbucks, Rockstar, Vitamin Water, etc. McDonalds is arguably the biggest brand, but.... Go to McDonalds.com and notice prominent links to follow them on Facebook and Twitter. There is more real estate dedicated to each of these than, for instance, to their restaurant locator:
Click on Facebook and a shadowbox pops up that asks, "are you sure you want to leave?"
It's almost as though McDonald's wants to promote Facebook / Twitter... but doesn't like the consequence of having it occur on Facebook / Twitter. It is also bizarre because the call to action is clearly "Become a Fan on Facebook" - so if I have offered to do so, why ask me to confirm again?
The strangest part is the messaging below the Yes / No. The language is not particularly inviting.... nor does it suggest that McDonald's itself is involved with their various accounts:
"You are leaving the McDonald's Corporation web site for a site that is controlled by a third party, not affiliated with McDonald's."
... But we hope that eventually you do decide to follow us on Facebook and Twitter!