Christmas has come early to Google employees: In an intriguing move, the search giant promised its 23,000 workers an extra $1,000 tax-free holiday cash bonus and an across-the-board 10 percent raise, starting in January. What's more, in response to staff surveys, Google also announced plans to roll a portion of workers' year-end target bonuses into their regular paychecks moving forward. (Watch a Fox Business report about Google's generosity.) What's behind Google's beneficence? Here, four theories:

1. Facebook and Twitter are poaching too many employees: This is Google's latest salvo in "its battle with competitors, especially neighboring Facebook... to secure talented staff," say Amir Efrati and Scott Morrison in The Wall Street Journal. Lots of Silicon Valley firms have been poaching Google's talent, but Facebook has been particularly aggressive — "roughly 10 percent of its employees are Google veterans." Will Google's "cash bomb" be enough to retain employees tempted by the prospect of becoming "stock-rich" millionaires in expected Facebook and Twitter IPOs? Wait and see, says The Street's Scott Moritz.

2. Google employees should thank federal antitrust officials
Forget Facebook, says Thomas Catan in The Wall Street Journal. Just six weeks ago, Google agreed to "scrap secret no-poaching agreements" with Apple, Adobe, Intel, Intuit, and Pixar to avoid a Justice Department anti-trust suit, and it's probably no coincidence that Google is using holiday pot-sweeteners to keep its crucial talent "from jumping ship" to five of its biggest tech rivals. Google said the no-head-hunting deals didn't affect wages, but antitrust officials disagreed.

3. Google's spreading the wealth
Google can afford to be generous, says The Street's Moritz. The search giant just reported a "blowout third quarter," and its stock price is up 13 percent this year. And switching year-end bonuses to regular paychecks is a win-win solution, says Felix Salmon in Reuters. Employees prefer raises to bonuses, and Google is "sitting on so much cash, and interest rates are so low, that the cash-flow benefits of a bonus system are de minimis."

4. The company is just maintaining its reputation as an "awesome place to work"
A cash gift and a fat raise is just one more "reason why Google is routinely at the very top of Fortune's list of best companies to work for," says Stan Schroeder in Mashable. And it's a neat way for Google to "show off its strength" during an economic downturn. As Gawker reported recently, Google already gives its employees "runners" to clean their apartments, run errands, cook, take out the trash — "whatever is needed," says Eyder Peralta at NPR. This is further proof that "Google is still an awesome place to work," says Business Insider's Henry Blodget, and will spend heavily to stay that way.