The Android Market has a far more lax approach to app approval than its counterpart Apple store. In fact, there is no approval process in place, and Google relies on users to police the offerings. If an app receives an unspecified number of complaints, Google will review it and remove the app if necessary. Google claims that only about 1% of all apps have had to be removed. This is in stark contrast to the Apple store which rejects about 20% of all apps submitted for review. The Android policies could cause future security concerns, as malicious apps could be found too late. Several people could have already been affected before the apps have been removed. I typically only download well known apps that have been available for quite some time, so I'm not too worried.