Having a smart phone means you are in touch with anyone, from virtually anywhere. Most of us use instant messaging clients such as Nimbuzz, eBuddy, Rocket Talk… most of which are provided as services from 3rd parties such as Nimbuzz. You should always note that your messages using their chat clients are routed to your chat partner via the 3rd party servers. This is not like logging onto a GTalk client that is routed through Google’s own servers.
Therefore, your chat client service provider would be an intermediary that has undertaken the activity of routing your chats to Google’s servers. Their security standards would not be those that Google follows. Therefore, you should be careful what you chat about, when using 3rd party chat service providers.