Google Inc. (NASDAQ:GOOGL) (NASDAQ:GOOG)  shares fell over 5 percent in extended-hours trading after the company reported fiscal first-quarter earnings of $6.27 per share, excluding items, on revenue of $15.42 billion for the period ended March 31, 2014. Wall Street expected the tech giant to post earnings excluding items of $6.40 a share on revenue of $15.52 billion, according to analysts polled by Reuters.

"We completed another great quarter. Google's revenue was $15.4 billion, up 19% year on year," said Google’s Chief Executive Officer Larry Page in the company’s first-quarter earnings statement. "We got lots of product improvements done, especially on mobile. I'm also excited with progress on our emerging businesses."

GAAP consolidated net income in the first-quarter was $3.45 billion, or $5.04 per share, compared to $3.35 billion, or $4.97 per share, in the same period a year-earlier.

Google is scheduled to host a conference call with shareholders at 4:30 p.m. Eastern on Wednesday, April 16, to discuss its quarterly financial results. Analysts will be watching for three key things: Mobile advertising revenue growth, the future of Google’s earnings following Motorola Mobility and the average cost-per-click.

Mobile Ad Revenue

“Their acquisitions and their innovation and their technological developments gets all the headlines, but really when you talk about Google it’s still all about ad revenue. Ad revenue, ad revenue, ad revenue,” Keith Bliss, senior vice president and director of sales & marketing at Cuttone & Co., Inc., said to the International Business Times.

Google said revenue for the previous quarter came in at $15.42 billion, a 19 percent increase compared with $12.95 billion in sales the company reported during the same period a year earlier.

“What’s interesting about Google, people forget ad revenue is still anywhere from 80 to 85 percent of their total revenue,” Bliss added. “While their buying drone makers and their floating high altitude balloons to bring internet around the globe, it’s really about the ad revenue right now until they get to a point where they transition over into some of those other lines of business which will take several years, if not decades to get there.”

Motorola Mobility

The net loss from discontinued operations in the first-quarter of 2014 was $198 million, Google said, compared to a net loss of $182 million in the first quarter of 2013. Net loss from discontinued operations in the first-quarter of 2014 included a pre-tax adjustment of $74 million related to the deferral of certain revenue for the Motorola Mobile segment.

“The good news about Google is that they’ve finally shed that albatross which was Motorola Mobility, so it’ll be interesting to see what the overall business complexion and future with google earnings primarily around that story,” Bliss said.

The Internet giant added that had the company presented Motorola Mobile as an operating segment, the Motorola Mobile segment revenue for the first quarter of 2014 would have been $1.45 billion, $74 million higher than what was included in net loss from discontinued operations.

Desktop & Cost-Per-Click

Google said aggregate paid clicks, which include clicks related to ads served on Google sites and the sites of our Network members, increased nearly 26 percent over the first-quarter of 2013 and decreased approximately 1 percent over the fourth-quarter of 2013. Meanwhile, the average cost-per-click, which includes clicks related to ads served on Google sites and the sites of network members, fell nearly 9 percent over the first-quarter of last year and remained constant from the fourth-quarter.

“But the other thing we’re looking for on the ad revenue is not only what the mobile revenue looks like as compared to the desk top. The desk top revenue has actually been a little bit stagnant and that’s primarily because the money that they get per click has been going down,” said Bliss. “That’s been shrinking because mobile is becoming everything. Google’s done an excellent job of capitalizing on that. Remember, they have about 80 percent market share globally from mobile devices and as long as they can continue down that line, and maybe the cost per click goes up, I expect to hear great things about that.”

Class A shares of Google (GOOGL) fell 5.27 percent to $34.20 in after-hours trading, while Class C stock (GOOG) dropped 5.38 percent to $526.48 following the company’s earnings announcement.