Get ready, Google (GOOG 2.21%) (GOOGL 2.26%) investors. Your favorite Internet search giant is set to announce quarterly earnings this afternoon, so it's time to start thinking about what to expect.

Analysts predict Google's revenue will rise 11.5% year over year to $17.8 billion, while earnings are expected to come in at $6.75 per share. But keeping in mind Big G isn't in the habit of providing quarterly guidance, it's worth noting Google stock jumped following last quarter's report despite falling short of Wall Street's estimates on both the top and bottom lines. So it's a great idea for investors to ask deeper questions to understand what really drives Google's underlying business.

Here are four such questions I'm keeping at the ready going into today's report.

Is Google really curbing costs?
First, Google stock jumped nearly 3% on Tuesday after the market cheered a Wall Street Journal report (may require subscription) stating the company is looking for ways to be more efficient in its spending. Specifically, Google's recently appointed CFO Ruth Porat -- who previously led an expense-reduction effort as CFO of Morgan Stanley -- is heading up an internal audit to identify ways to streamline costs, as well as revenue and accounting systems. WSJ also noted a recent curb in hiring, as Google added "just" 1,819 new employees in the first quarter to bring its total to 55,419. That might sound like a lot of new talent, but it's actually Google's lowest number in almost two years, and well below its average of over 2,400 new employees per quarter since then.

That's not to say Google will stop spending altogether. After all, the company ended last quarter with almost $65 billion in cash on its balance sheet, so don't be surprised if we continue to see billions in capital expenditures allocated to production equipment, data center construction, and the occasional opportunistic purchase of real estate to sustain growth going forward.

Are currency headwinds abating?
Next, almost 58% of Google's total revenue last quarter came from international markets, so it's no surprise foreign exchange had a significant effect on its top line. As it happens, that effect hasn't been favorable of late; the continued strength of the U.S. dollar last quarter had a gross negative currency impact of $1.1 billion to revenue during the quarter, and a net impact of $795 million even after the benefits of Google's hedging program.

"If these currency trends persist," then-CFO Patrick Pichette warned at the time, "FX headwinds would obviously continue to impact our results in 2015."

Consequently, this begs two questions: First, exactly how severe were these FX headwinds in the soon-to-be-reported quarter? And second (for perspective), how strong are Google's businesses excluding the negative (or positive) effects of foreign exchange? Investors should be listening closely for Porat to provide insight on both fronts during this quarter's call.

How is the core ad business performing?
We also can't forget Google's bread and butter advertising business, which represented an overwhelming 89.9% of total revenue last quarter, up from 88.9% in the same year-ago period. This will be broken up into two parts: Growth from Google's own sites (up 14% last quarter to $11.93 billion), and growth from Google Network Members' sites (up 1% last quarter to $3.58 billion).

Google will also offer insight into its aggregate paid clicks, which rose 13% year over year last quarter, as well as aggregate cost-per-click, which declined 7% last quarter and measures how much Google makes per ad. Relatedly in an out-of-character move last quarter, Pichete also chose to clarify that the recent drop was not due to trouble monetizing mobile as some analysts had speculated, but rather due to huge increases in viewership on YouTube. In turn, this drove higher volumes of TrueView video ads being seen, which Pichete elaborated "generally reach people earlier in the purchase funnel, so across the industry tend to have a very different pricing profile than they would have on a typical performance search ad."

Translation? TrueView video advertisements monetize at a lower rate than your typical ad, so any further year-over-year declines in Google's aggregate cost-per-click figure shouldn't alarm investors.

How quickly is the "Other" revenue category growing?
Finally, don't forget Google is working hard to diversify outside of search, with revenue from the "Other" category climbing 23% year over year last quarter to $1.75 billion. But that growth was driven almost entirely by Google Play store sales, and held back by a combination of declines from Google's Nexus products and foreign exchange. In particular, recall two quarters ago Google stated while the Nexus 6 smartphone was well received by consumers, the company had trouble securing inventory to meet demand. Management didn't elaborate last quarter on whether those inventory bottlenecks have been addressed, so I would love to hear some further clarification on the topic during this quarter's call.

And finally, listen for updates on Google's various "moonshot" initiatives, including but not limited to self-driving cars, robotics, Google Fiber Internet projects, and low flying satellites to provide Internet connectivity to the far reaches of the globe. To be fair, these are ambitious, longer-term projects (think 10 years or more) with little chance of delivering meaningful revenue in the near future. But from a long-term investor's standpoint, the promise of these moonshots represent some of the most exciting wild cards for owning Google stock over the long haul.