Narrow - Narrow helps you build a targeted audience and increase your influence on twitter.
Hum - Songwriting for iPhone
Followerion - Followerion is the most trusted site regarding how to get more followers on twitter.
Songcraft.io - A platform for songwriters to write, organize & collaborate.
Follow3rs - Follow3rs enables you to add more followers to your Twitter account and become prominent in no time at all.
Tape It - App for songwriting & audio recording.