To look at it in simply this is the only way I see it.
Java/Flash/Macro is a list of commands to do stuff without you seeing whats going on. So as such easy to plant some thing on PC or log what your doing.

They are a threat in a way. But really depends what you have on your PC. In the years I have been on a PC. I have only ever had a few virus' and my Firewalls have only ever reported on a few random port intrusions.

Turn em back on and let the woman shop