Yammer CEO Predicts End Of Silicon Valley

There is a pretty fascinating debate happening right now on David Sacks’ Facebook page. Exactly one month after the Yammer sale to Microsoft closed, Sacks is feeling pretty bearish about the startup ecosystem.
“I think Silicon Valley as we know it may be coming to an end …,” Sacks posts, arguing mainly that because major Internet companies (like um, Microsoft?) are on the prowl for innovative ideas, it’s too risky and costly for entrepreneurs to attempt to create successful new companies.
“How many [viable] ideas like that are left?” Sacks, who was a TechCrunch50 winner, asks?
“An infinite number — human creativity is limitless,” responds the infinitely more positive Marc Andreessen, “Which doesn’t make it easy, but does mean the opportunity is unending.”
Andreessen then refutes Sacks’ argument point by point, basically asserting that larger companies are, in many cases, less equipped than startups to execute on novel and world-changing ideas (Apple Ping anyone?), as they care more about stability than change.