Zynga, though still a viable company, is also struggling to get some zing back in its stock. There must be a lot of "angry birds" out there, who are a bit miffed that Zynga could not replicate that momentary success with another brief, but profitable, fly by.
Away from the gamers, and into the realm of theme restaurants: Anyone remember Rain Forest Cafe??? Neither do I. Check that tropical stock out. Good luck finding it in the jungle of failed fads.
Although this IS an emotional statement, I have to say it: I hate "fad stocks," be they digital game makers, theme restaurants, or pet rocks. They are like your dream date who turns out to be a dud. (There may be some of you reading this old enough to remember what game that line comes from!)
(Read more: Candy Crush? WhatsApp? Sure looks like a bubble)
There are some, including a few of my colleagues, who say that King Digital is different. It creates, not acquires, new games with a talented in-house team; it doesn't rely on Facebook, like Zynga did, for its distribution; it's valuation is cheap relative to other companies in the same space and its revenues and profits are growing nicely.
Wall Street is littered with hot stocks, and fads. For every Mattel and Hasbro, there are countless Colecos, 4Kids or Furbie Factories.
Like those failed fads, King Digital, thus far, has one thing going for it … Candy Crush. Seventy-eight percent of the company's money currently comes from the Candy Crush craze. For me to get sweet on this stock would require more proof that this stock is more worthy of a long-term relationship than a mere crush. And there are far too many examples of stock-market crushes that turn out, simply, to be one-night fads.
— By Ron Insana
Ron Insana is a CNBC and MSNBC contributor and the author of four books on Wall Street. He also delivers a daily podcast, "Insana Insights," and a long-form weekly version, both available on iTunes and at roninsana.com. Follow him on Twitter