It's such a perfect image, reflecting the cyclical nature of, well everything (economics - boom and bust; political parties - boom and bust; the building and decaying of the middle class, of the ideological spectrum, of openness and xenophobia, they all go in circles). We think in spectrums, but our society functions more like a wheel, or perhaps a gear.
The Ouroboros also demonstrates how new things don't replace old ones, but rather emerge from them. It's social evolution, creative destruction, whatever you want to call it - the old begets the new which cannibalizes the old and the cycle repeats.
You can see why I love the picture above, probably snapped by someone's iPhone from the gallery.
And the cycle continues...
UPDATE 17 March, 2014: Rumours of the left's death were premature, to say the least. My own prediction of a right-wing takeover wasn't completely accurate, either. The ideological pendulum - which had been careening off to the right - is now swinging back to the centre, and the left.
I note the "and the left" part. For those looking for ground to stand on, I wouldn't recommend careening too far after that pendulum, 'cause it's just going to swing right back. The best place to be, as always, is smack in the centre.