Keeping in touch with friends and loved ones can be challenging. These apps will help you say "hello" and celebrate the valuable people in your life.Apple appsJustWink Greeting Cards (Free)* American Greetings brings you this playful collection of greeting cards that you can send via text or snail mail. (Mobilewalla Score: 89/100)Appygraph (Free) Quickly build a colorful greeting with this starter pack of 100 free card templates. (Score: 89/100)someecards ($0.99)* Make your friends laugh when you share all the hottest new user-created someecards found in this app. (Score: 88/100)Birthday eCards ($1.99) Create custom virtual birthday cards from this collection of templates, and add your own photos. (Score:80/100)Hallmark Go Cards (Free) This app sends greetings for you instantly when you can't get to the Hallmark store. (Score: 77/100)Android appsTouchnote Cards (Free)* Turn your Android photos into cards and postcards, and have them printed and mailed to your loved ones and friends for small fees. (Mobilewalla Score: 88/100)Funny Greetings, ecards 12000+ (Free) Choose from 12,000 special-occasion e-cards that can be translated into multiple languages. (Score: 85/100)Free Funny Rotten Ecards (Free)* Rotten's huge user following creates new greeting cards each day; use the app to share them with your friends. (Score: 84/100)Greeting Card Guide (Free) A series of cheerful templates to help you build greeting cards for most standard holidays and occasions. (Score: 77/100)Greeting Card Maker Pro ($0.99) Create custom postcards, and have them printed and sent via mail for 99 cents each (one comes free with purchase of the app).(Score: 77/100)An asterisk* denotes availability on Apple and Android.Mobilewalla is a search-and-discovery engine using breakthrough technology to score every app to help consumers navigate the mobile application marketplace. Apps are scored using an algorithm that weighs several characteristics, including user ratings, position within category and staff recommendations. For more app intel, go to www.mobilewalla.com. Anindya Datta is a technologist and founder of Mobilewalla.