This is completely unscientific, but once something gains this much hype I just get the gut feeling that the value has disappeared for investors. If the likes of Ashton Kutcher are there, the game's up, the secret's out - these assets are no longer undervalued. If I'm an investor, it's time to pack up and move on to find the next market inefficiency, cause I really doubt it's in YC funded startups anymore.