Mobile UC tools can integrate with corporate e-mail systems. Users won't have to open up their laptops to check mail. The same goes for instant messaging. Users can chat with associates regardless of their location or network coverage.
Because mobile messaging can traverse public networks, security is a necessity. Also important is users' authentication to allow them to access IM and e-mail applications from their devices. A true mobile UC deployment will authenticate users and the messages exchanged will be secured by the system regardless of the physical location of the user.