According to the TechCrunch blog, Google (Nasdaq: GOOG) has invested between $100 million and $200 million in FarmVille parent Zynga. Let's hope that this growth effort doesn't wither on the vine, like so many of the search giant's prior purchases.

The Zynga investment may prove a shrewd move on Google's part, especially as it ramps up its hiring efforts for an online gaming division. Zynga's support for smartphones powered by Google's Android should also grow dramatically with Big G as a minority investor.

TechCrunch's sources also paint a glowing picture of Zynga, projecting at least $1 billion in revenue next year, with healthy margins to boot. However, I also keep thinking back to a report by gaming blog Kotaku two months ago, indicating that Zynga may have jumped the shark. It detailed how Zynga was losing millions of active users in May, after Facebook blocked its ability to use notifications and gift requests.

Zynga has rightfully expanded its efforts outside of the leading social-networking site, but isn't the realm of casual and social app-gaming getting awfully crowded these days? Even Viacom (NYSE: VIA) and Disney (NYSE: DIS) have followed Electronic Arts (Nasdaq: ERTS) in making social gaming acquisitions recently.

Google may also face an uphill challenge in swaying developers to embrace its different platforms, now that it's an interested cheerleader with a stake in Zynga. 

Despite some notable exceptions, Google has made several lousy investments in the past:

  • It forked over $1 billion for a 5% stake in AOL (NYSE: AOL), dumping the shares a few years later when AOL was worth significantly less.
  • Google struck a deal that could have originally been worth as much as $1.2 billion over three years in incentives for radio advertising specialist dMarc. That real-world expansion didn't exactly pan out, either.

Google also has a bad habit of betting on the wrong horse. It acquired microblogging site Jaiku instead of saving up for Twitter. It launched social networking site Orkut instead of eventually hopping aboard News Corp.'s (NYSE: NWS) MySpace or Facebook. It bought -- and subsequently shuttered -- Dodgeball instead of pairing up with Foursquare.

Yes, Google did wager wisely on YouTube. DoubleClick should be another winner. However, investors should wait and see whether the dot-com rock star can prove itself equally worthy in social gaming.

What are your favorite or least favorite Google acquisitions? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz still uses Google a lot in his daily life. He does not own shares in any of the companies in this story, except for Disney. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.