The best replacement for messages is you messages.

The best alternatives to messages are rated as following:
★★★★★  you messages
★★★★★  messages
★★★★  ichat
★★★  sms
★★★  adium
★★  runnables
★★  mms messages
★★  methods
★★  syslog
★★  greetings
★★  facetime
★★  events
★  phone calls
★  text messages
★  desktop blackberry
★  thoughts
★  sms text messages
★  i messages
★  mms
★  notifications
  imessages
  blackberry messenger
  positive messages
  green
  u messages
  two sided messages
  nonverbal messages

Your alternative for messages is not listed? Suggest!
Speaking about messages, one probably shouldn't forget about pictures.

Other search terms related to messages and their ratings are:
★★★★★ pictures
★★ images
You have in mind a companion for messages and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of messages in all years. Click on graph for more.
messages
you messages
messages