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 investing thesis.

What: Shares of Trulia (UNKNOWN:TRLA.DL) rose nearly 33% in Thursday's late trading following reports that it's in talks to be acquired by Zillow (NASDAQ:ZG). Shares of Zillow also jumped more than 15% on the news.

So what: According to Bloomberg, "people familiar with the matter" say Zillow could value Trulia at as much as $2 billion, and that a deal could be announced as soon as next week. Curiously, the news arrives a little more than a month after Trulia was reportedly in talks to acquire its own smaller rival, Move, in a deal valued at more than $700 million to help the two companies better compete with Zillow.

Now what: With that in mind, remember that the alleged talks are ongoing, and certainly aren't guaranteed to result in a deal. Considering today's massive jump has increased Trulia's market cap to almost exactly the reported acquisition value, I wouldn't blame Trulia investors for taking profits today and putting them to work elsewhere.