From the description, Bouncer is like a security agent that scans the marketplace for malware, relying on signatures of known malware to do its job. Besides looking for malicious applications, Bouncer also analyzes “new developer accounts to help prevent malicious and repeat-offending developers from coming back.”

The idea, as Hiroshi described it, is to provide an “automated scanning of Android Market for potentially malicious software without disrupting the user experience of Android Market or requiring developers to go through an application approval process.” Sounds good to me.