The only downside to an Open Source platform are the people that take advantage of it to ruin lives. Trojans are one the most annoying and irritating things that plague not only open sourced software but all OS’s. The latest attack on Android devices also plays by a few new rules. This Trojan can record your phone calls, store the file to your SD card and the attacker can retrieve that call when ever they want.
You can generally keep yourself safe by checking what an application wants permissions to do. For instance if a game wants to record audio, intercept outgoing calls, read phone state and identity, then this game might not be as innocent as it looks. There are other solutions available to help further protect you valuable information. you can install a mobile app version of LookOut. This is a mobile security app that can help you stay clear of trouble. Alternatively, in CM7 build, you can actually deny applications from having certain access. Although that method may prevent the app from functioning, it would prevent you from any harm.
Personally, I have nothing to hide and they would soon get board listening to me talk to my wife and friends over mundane things. I just wish i knew when it was recording so I could give them something juicy to listen too.