It's pretty clear how investors and shareholders feel leading up to Facebook's (NASDAQ:FB) second-quarter earnings announcement scheduled for Wednesday, July 23. Facebook shares have enjoyed a 4% plus increase in the past week. Shareholders are obviously expecting more good things from the social media giant, just as Facebook delivered last quarter. But is that reasonable, given Facebook's tremendous growth leading up to this point? Without a doubt.

Investors are right to expect yet another stellar quarter from Facebook, and many industry pundits feel the same. But that doesn't mean Facebook isn't facing challenges, not the least of which is increasingly difficult comparables. In other words, as Facebook's business matures, its results are being measured against consistently higher quarter-over-quarter, and year-over-year, numbers. But if we've learned anything about Facebook in the last year, it's to not underestimate CEO Mark Zuckerberg and team.

Second quarter expectations
As we approach Facebook's Q2 earnings release, investors aren't the only ones expecting significantly better results. Analysts have steadily increased earnings-per-share estimates over the last several months, and now have a consensus target of $0.32 a share.

If Facebook is able to deliver anything close to earnings expectations, all the warm and fuzzy feelings of the past couple of weeks will have been justified. In Q2 of 2013, Facebook reported $0.13 per share in earnings on a GAAP basis, and $0.19 after removing one-time expenses. Either way, the consensus $0.32 a share analysts are expecting would be outstanding.

In terms of revenue growth, some industry insiders expect Facebook to deliver about a 60% overall improvement compared to 2013, and a 66% improvement in ad revenues. At this stage in Facebook's growth, those would be phenomenal results. Now consider if Facebook is able to grow its monthly average users, or MAUs, at the same clip it did last quarter, it will have nearly 1.5 billion users. To put that in perspective, upstart social media wannabe Twitter (NYSE:TWTR), despite its early growth phase, is already having to battle slowing user growth, and it has one-fifth the number of users as Facebook.

Growth drivers
Despite all the positive feelings, the question is how can Facebook deliver what most everyone expects to be a blow out quarter? That's where things really get exciting for Facebook fans, because there are multiple ways it can, and will, accomplish the feat.

App install ads are quickly becoming a key driver of growth for Facebook, and that's not expected to slow anytime soon. If Facebook is able to deliver the expected 150 million app downloads in Q2, it would generate an estimated $300 million in revenue from app install ads alone. Though late to the party as usual, the success of app install ads is why Twitter recently unveiled its own mobile app ad platform. Of course, Twitter's not expected to make much of a dent, even as Facebook continues to gain market share from industry-leading Google.

App install ads are hardly the only means for Facebook to maintain its stellar growth rates, however. More and more marketers are shifting their ad dollars to digital, and Facebook  is quickly becoming the platform of choice. Facebook's emphasis on targeting small businesses will continue to pay-off as well. Facebook already has over 1 million small business customers, and its recent string of seminars directed to small business owners should boost that already impressive number even further.

Continued growth in mobile ads, combined with an unprecedented amount of digital advertising spend for several years to come, also bodes well for Facebook. Certainly Twitter will continue to dabble with ways to try and eat into Facebook's share of ad spend, just as Facebook is attempting to do to Google. The difference is, Facebook is actually doing it, whereas Twitter has yet to prove itself.

Final Foolish thoughts
There's a reason that nearly every analyst that follows Facebook has the equivalent of either an outperform or buy recommendation: there's substance behind all the good tidings. With so many revenue drivers already beginning to make an impact, the only surprising result would be if Facebook didn't meet, or exceed, the market's lofty expectations.

Now consider that Facebook's multiple acquisitions aren't likely to boost revenues this quarter, nor will video ads or the monetization of Instagram kick-in just yet. As Facebook fans prepare for yet another blowout quarter, it's next year and beyond that should really have investors feeling giddy.