Socialkeeper - Cultivate your friendships
Felt for iPhone - Handwritten cards for the modern world
FaceCat - Chat anonymously with your friends
Thankster - Automagically send hand written cards
Bond - A simple app that reminds you to keep in touch with people
Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.