While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of LinkedIn Corp. (LNKD.DL) climbed 3% this morning after BMO Capital upgraded the online professional network from "Market Perform" to "Outperform."

So what: Along with the upgrade, analyst Daniel Salmon raised his price target to $270 (from $235), representing about 19% worth of upside to yesterday's close. While value investors might be turned off by LinkedIn's sharp share-price rise over the past two years, Salmon believes that there's plenty of room to run given several growth opportunities, particularly in China, that management sees in the future.

Now what: BMO sees quite a few catalysts ahead for LinkedIn. "We believe there are several new stories emerging that will raise long-term growth expectations; in particular, we believe LinkedIn is preparing to formally launch in China," noted BMO. "We are also positive on LinkedIn's increasing focus on salespeople ... highlighted by an expected stand-alone product that should ramp during 2015. ... Finally, the Talent Solutions story now includes the recently released mobile app and a potential price increase in Europe in 2014 or in 2015." More important, with the stock a bit sluggish of late -- down about 10% over the past three months -- and the balance sheet continuing to boast $2.3 billion in cash, LinkedIn's downside might be limited enough to bet on that bull talk.