Whether it's a selfie or a picture of your latest meal, Instagram is the king of photo sharing apps. The app saw 43,944,000 average unique users last year, a 34% increase year over year, according to Nielsen.

Price: Free (iOS, Android)

Google+ has evolved from a social network into the connective tissue of Google's other apps like Gmail and YouTube, and that helped the app reach 48,385,000 average unique users last year.

Price: Free (iOS, Android)

Facebook caused an uproar when it broke off messaging into a standalone Facebook Messenger app. The move worked, however, and the app saw 53,713,000 average unique users in 2014.

Price: Free (iOS, Android)

Regardless of how popular messaging has become, people still need email, and Gmail is the most popular email app around with 72,405,000 average unique users.

Price: Free (iOS, Android)

Google Maps is the best maps app out right now, and it's a must for anyone who uses public transit. Google Maps saw 79,034,000 average unique users last year.

Price: Free (iOS, Android)

Sometimes you need an app to download other apps. Google's online store, Google Play, comes installed on most Android phones and snagged fourth place with 84,968,000 average unique users.

YouTube's mobile app is still the best place to watch online videos on your phone. The app saw 88,342,000 average unique users last year, resulting in a 26% year-over-year increase in downloads, according to Nielsen.

Price: Free (iOS, Android)

People love to Google things, and the best way to do that on your phone is with the Google Search app. Google Search was the second most popular app of 2014 with 90,745,000 average unique users.

Price: Free (iOS, Android)

Facebook's main app was the most downloaded app of the year, with an incredible 118,023,000 average unique users. It's also gained some new users since last year, with a 15% year-over-year increase, according to Nielsen.

Price: Free (iOS, Android)

The Best iPhone Apps Of The Year, According To Apple >>