Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our thesis.

What: Shares of Zynga, (NASDAQ:ZNGA) rose nearly 24% Friday after the company revealed better-than-expected fourth-quarter results, a new acquisition, and plans to reduce its workforce by 15%.

So what: Quarterly sales fell 43.3% year over year, to $176.4 million, which translated to an adjusted net loss of $0.03 per share. By contrast, analysts were expecting Zynga to post a wider loss of $0.04 per share on lower sales of $138.42 million. Meanwhile, Zynga's fourth-quarter bookings -- a key measure for in-game virtual goods purchases -- also fell 44%, $147 million.

Zynga also announced it will acquire mobile game developer NaturalMotion for approximately $527 million, including $391 million in cash and roughly 39.8 million in shares of Zynga stock. The transaction is expected to be accretive to Zynga's non-GAAP earnings, and generate bookings of $70 to $80 million in 2014. 

Going forward, Zynga expects revenue in the current quarter to be $155 million to $165 million, with an adjusted net loss of $0.01 per share on bookings of $138 million to $148 million. Analysts were modeling a first quarter loss of $0.02 per share on sales of $147.1 million. Better yet -- and thanks largely to the acquisition -- full-year 2014 bookings are expected to be in the range of $760 to $810 million, or an improvement over Zynga's 2013 bookings of $716 million.

Now what: Zynga also claims that part of its strategic rationale for the acquisition is that it "accelerates mobile growth" -- an interesting assertion considering Q4 mobile bookings actually fell by 5.5%, to $51 million during the same period last year. Bookings did increase sequentially, however, from $46 million in the third quarter.

Even so, I can't help but be skeptical considering Zynga's acquisition history. Remember, Zynga acquired Draw Something creator OMGPOP in early 2012 for $180 million, only to take a hefty impairment charge after shuttering its doors less than a year later.

In the end, given the risk of another bad acquisition and the fact that Zynga's bookings are still coming in below GAAP revenue, I'm perfectly happy remaining on the sidelines.