The most popular apps of 2013

In 2013, iOS and Android users downloaded apps an estimated 100 billion times, by far a new record. Here are the most popular free apps of last year, according to Apple's iTunes Store.

Candy Crush Saga

(iOS, Android; free)

The puzzle game not only led the list of most downloaded apps, it also garnered a staggering 4 million comments from reviewers on Google Play and iTunes. The aim of the game is to match candy shapes across levels of increasing difficulty. The game is free, but in-app purchases from addicted gamers have proved so lucrative that Candy Crush developer King.com is lining up investors for a highly anticipated IPO.

YouTube

(iOS, Android; free)

The go-to website for homemade videos and professional content from entertainment giants for many years, Google-owned YouTube is also a must-have app on mobile devices. The app had a series of updates and improvements last year on both Android and iOS platforms, adding searchable playlists and other user-friendly features. After feuding with Apple, which removed the app as a standard feature on its iOS 6 operating system, Google redesigned YouTube for Apple's new iOS 7 system and the app zoomed to No. 2 among most downloaded free apps in 2013.

Temple Run 2

(iOS, Android; free)

Immersive gameplay and stunning graphics drove this "endless-runner" game to the No. 3 spot on 2013's most downloaded free app list. The original Temple Run, launched in 2011, helped show that tiny smartphones could be big for gaming and was the most downloaded game of 2012. The goal of both versions is to escape with treasure by running, jumping and sliding away from demon monkeys. Compared to the original, Temple Run 2 features bigger visuals and bigger monkeys.

Vine

(iOS, Android; free)

This social media app from Twitter created a sensation when it was released last January, ending 2013 as the year's fourth-most downloaded free app. Vine allows users to create looping six-second videos that can be attached to tweets or shared directly with Twitter followers. Despite their brevity, many videos display such remarkable creativity and ingenuity that several websites feature nothing but Vines, helping the best videos to go viral.

Tech Bytes

Learning curve

As colleges reopen for the spring semester, many students will return to the classroom with their attention divided. A University of Nebraska-Lincoln study found that a typical student accesses a smartphone about 11 times a day while in class. Most common activity: texting, followed by checking email. More than 80 percent of students admitted their in-class smartphone use interfered with their learning. -- Peter King
Digital music sales drop

After years of growth, digital music sales dropped in 2013 for the first time. Billboard reports that sales of full albums and individual tracks both fell, as did sales of physical CDs. Billboard said the decline can be attributed to the growing popularity of streaming music services. One category that saw growth: vinyl albums. Sales of the old-tech format rose 32 percent in 2013. -- Peter King

BlackBerry sues Seacrest's firm

BlackBerry filed a lawsuit against a company co-founded by "American Idol" host Ryan Seacrest that offers a physical keyboard that can be attached to some of Apple's iPhone 5 models. The company, Typo Products, is taking preorders for the $99 keyboard, which features angled miniature keys similar to those used on many of BlackBerry's devices. BlackBerry said Typo's keyboard infringes its own design. -- Reuters