Zynga chief operating officer John Schappert has stepped down amidst a seemingly endless stock slide.

The move comes as no surprise, as the market of FarmVille is looking increasingly likely to buy that good old farm in the sky. Zynga’s shares  dropped from $14 in March to under $3 in the first days of August, so the outfit has seen better days. The company’s market capitalization is $2.26 billion.

Zynga did not name Schappert’s successor just yet, but he or she is likely to face quite a few challenges. As for Schappert, this EA veteran should have no trouble finding greener pastures.

Looking at the big picture, it’s hard not to state the obvious. With Zynga losing billions in market cap and Facebook trading at half its IPO price, with no bottom in sight, the social notworking bubble is bursting.

At some point hype always gives way to sanity and in this particular game of musical chairs someone just pushed the stop button.