If you want to make the most of an existing Android phone or tablet, our list will help you keep in touch with the most important people in your life, all from your handy Android. Google Voice (Free) Google Voice integrates seamlessly with your Android phone, giving you a single number that can ring through to as many devices as you like. Hand it out to whomever, and use the service's spam and blocking filters to protect your privacy. You can also use Google Voice make cheap international calls, but my favorite features are sending and receiving free text from any device—even my desktop PC. Hangouts (Free) Google Talk is dead, long live Google Hangouts! This app can not only send instant messages to other Google users, but it can also do video chatting for free. Users lucky enough to have Android 4.4 can also use it to manage their SMS messages, and Google+ users can enjoy video conference calls with up to twelve participants. imo (Free) This handy messaging client lets you connect with Facebook, Google, MSN, Yahoo!, ICQ, Jabber, Steam, and AIM services. It also lets you chat with other imo users, and post Twitter-esque public broadcast messages to the service. While instant messaging has declined in the face of texting, this app lets you reach just about anyone—instantly. Viber: Free Messages & Calls (Free) Viber distinguishes itself from other free voice and texting apps by adding your computer as a communication device. From your Android, you can seamlessly transfer a voice call to the Viber PC app and keep talking, or pick up a text message conversation already in progress. With a growing list of fans, Viber is well positioned to make talking and texting a little easier (and cheaper). TextSecure :: Private SMS/MMS (Free) If you're worried about the NSA or anyone else peeking at your text messages, consider TextSecure. Messages sent to other TextSecure users are encrypted over the air, but the app will also encrypt all of your text messages when they're at rest on your phone to keep them away from prying eyes. We first reviewed the app when it was in Beta, but it's since had a full version release and is ready for prime time. RedPhone :: Secure Calls (Free) The companion to TextSecure, this handy app lets you make encrypted calls over the developer's secure VoIP network to other TextSecure users. I particularly like that it works with your existing dialer and phone number, alerting you when another RedPhone user is on the line and the call can be encrypted. If all those PRISM and NSA headlines have you worried, be sure to give this app a try. Facebook (Free) Those addicted to the big blue social network can now stay connected at all times thanks to the Facebook Android app. You can use it to browse the entirety of Facebook and chat with other users, and you can also access all the settings available on the website. It's a brilliant mobile adaptation of a sprawling service. Circle of 6 (Free) This unique app is for those dangerous situations when you need to quickly (and discreetly) get help from your friends. Two quick taps sends one of three pre-written text messages to as many as six of your contacts. One message sends your GPS location and a request to be picked up, while another asks your friends to quickly get in touch with you. The app also includes links to the RAINN and Love is Respect hotlines. Plume for Twitter (Free) Sure, there are plenty of ways to fire off a 140-character Tweet, but users looking for more control should consider Plume. This powerful Android Twitter client lets you change all sorts of settings, right down to the LED color used to alert you of a message. My favorite feature is muting, which lets you suppress users, and even specific words, from your timeline.