What: Shares of TripAdvisor (NASDAQ:TRIP) fell as much as 11.5% early Friday, then partially recovered to trade down 7.6% as of 12:00 p.m. after the online travel specialist reported weaker-than-expected third-quarter results.

So what: Quarterly revenue rose 17% year over year (25% on a constant-currency basis) to $415 million, including a 6% increase (14% at constant currencies) in click-based advertising revenue to $261 million, a 20% jump from Display ads to $42 million, and a 56% increase from Subscription, Transaction, and other revenue to $112 million. Adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) climbed 9% (26% at constant currencies) to $130 million, and adjusted net income rose 9.9% to $78 million, or $0.53 per diluted share.

Analysts, on average, were anticipating adjusted earnings of $0.55 per share on revenue of $430.2 million. 

Nonetheless, TripAdvisor CEO Steve Kaufer insisted, "We are focused on evolving our products to enable more users to not only plan and compare but also book on TripAdvisor. While still in the early days of this evolution, we continue to make tremendous strides toward our long-term growth objectives and are helping more and more travelers around the world book the best trip."

Now what: In the subsequent conference call, Kaufer elaborated that TripAdvisor's accelerated roll-out of Instant Booking in two of its largest markets in September contributed headwinds of roughly $10 million to revenue, and $8 million to EBITDA in the third quarter. Keep in mind TripAdvisor is still working hard to onboard new partners and improve monetization for the young Instant Booking platform.

CFO Julie Bradley also noted the fourth quarter will have a full-quarter contribution from TripAdvisor's accelerated rollout of Instant Booking, and TripAdvisor also expects to begin onboarding booking.com later in the quarter. As a result, and accounting for foreign exchange rates as of today, TripAdvisor now expects full-year 2015 revenue growth to be in the high teens, while EBITDA should have "slightly negative" growth.

For perspective, three months ago TripAdvisor's 2015 guidance called for higher 2015 revenue growth in the low- to mid-20%s, with EBITDA growth in the low- to mid-single digits. 

In the end, it's hard to blame investors for taking a step back given TripAdvisor's freshly reduced guidance and quarterly miss. But we should also keep in mind the company is looking at its future through a long-term lens, and Instant Booking is a crucial way for TripAdvisor to better capitalize on consumers' increasing reliance on mobile and wearable devices. While it's certainly not ideal to have an early rollout of the platform negatively affect revenue and earnings in the near term, it should also put TripAdvisor in a better position to improve monetization sooner than later.

Steve Symington has no position in any stocks mentioned. The Motley Fool owns shares of and recommends TripAdvisor. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.