Maybe this is a temporary issue. I will check later in the night today and update/close this thread. [2013-02-27] For most of the world, this issue should now be resolved and non-repro, and the general consensus is that it was a Google glitch!
Displayed results (larger image):
This has no resemblance to the content displayed by Google.
I am not tagging this as a bug as it seems unlikely that this is an issue within Stack Exchange control.
stackoverflow on the US or some other region specific site, this effect is not observed. But searching explicitly for
stackoverflow doioig brings up a slightly different result: