Changes

# Accidental/malicious install: "Hey, we suddenly found a new SketchyWare.dll plugin on your system. Did you actually want to use it?"

# Performance: Another is the "Java makes my system asplode when a page loads, but sometimes I want to use it" problem.

# Security: Users who don't trust Flash, as well as giving us a way to soft-block a plugin that a user needs to use on legit sites (YouTube, intranet, whatever).