• Apple reported record revenue numbers this week, along with record iPhone and iPad sales.
• As if the App Store isn’t packed enough, 2013 will bring an estimated 435,000 new apps to iOS users – further aggravating discovery challenges for app marketers.
• Across iOS, Android, and RIM, Facebook is the No. 1 app in the U.S., with nearly 86 million unique visitors per month.
• Experts believe 2013 could be a year of explosive tablet growth, as global tablet shipments are expected to reach 145 million. What does this growth mean for mobile marketers?

This week, Apple reported its first quarter earnings, revealing the company sold a record 47.8 million iPhones, 22.9 million iPads, 4.1 million Macs and 12.7 million iPods. In total, some 75 million iOS devices were sold during the quarter. “We’re thrilled with record revenue of over $54 billion and sales of over 75 million iOS devices in a single quarter,” said Tim Cook, Apple’s CEO. “We’re very confident in our product pipeline as we continue to focus on innovation and making the best products in the world.” AllThingsD has more here.

A recent year-end adeven report forecasts that the Apple App Store will boost its inventory this year. More than 435,000 new apps are expected to launch in the already jam-packed App Store, creating more user acquisition headaches for app developers and marketers. “Growth in terms of App Store size will continue to increase steadily as it has during the past few years, but it also points to a steady climb in the number of apps that fall into its ‘zombie’ category, which accounted for 60 percent of apps in June, but climbed to 64 percent in its most recent tally,” reports Darrell Etherington in TechCrunch. Zombie apps are those that aren't ranked and so have very little chance of being discovered by users.

While the competition is fierce, Facebook sits atop the crowd as the most popular app brand in the U.S., according to comScore. In 2012, the Facebook app enjoyed 85.5 million monthly unique users across iOS, Android and RIM platforms. Of note, Facebook not only has the largest number of users, but also the highest level of engagement. And while Facebook sits at number one, Google apps (including maps, search, and YouTube) occupy slots 2 through 6. Seth Fiegerman of Mashable has more.

New research from ABI Research suggests that 2013 could see dramatic growth in tablet sales. A projected 145 million tablet shipments are set to hit the shelves across the globe this year, meeting the demands of tablet-crazed consumers, reports Mobile Entertainment’s Daniel Gumble. This boost also produces a huge opportunity for marketers. “The concept of mobile advertising started with smartphones but tablets are changing everything, rapidly establishing themselves as universal media players (TV programs, movies, radio, news, magazines) in a way never achieved through ‘personal’ computers,” said Magna EVP and Director of Global Forecasting Vincent Letang to MediaPost.