One of the biggest obstacles that employees faces at IBM is how they can communicate with directors and up... They may not feel comfortable approaching the boss, and as a result of this apprehension, many employees may choose to avoid bringing up important points, thus blocking the flow of communication.
Having an "open door" policy (not only on paper) where your employees feel comfortable bringing anything to your attention, at any time, can be immensely beneficial to your business's internal communication, not to mention it will make you more approachable.
If they are not approaching you, always remember they are probably talking to fellow employees (check in with employees on a regular basis).
"