Summarize:

This will undoubtedly lead to the question of getting back together, and will sabotage your chance of establishing a platonic friendship. While maintaining a friendship with anyone, ex or not, requires occasional contact via phone or computer, don't start texting or calling your ex on a daily basis. This will inevitably create a false hope of getting back together. If either you or your ex is getting too attached and old feelings start to arise, then don't force the friendship. This is probably a sign that the breakup is too fresh, and that you need to spend more time apart.
Don't have sex with your ex. Don't fall back into old patterns. Know when you back off.