WEP is "Wired Equivalent Privacy". It wasn't supposed to be very strong - about a secure a regular wired network. However, it wasn't known back then just HOW weak it was. As a stopgap measure, WPA PSK (TKIP) was created. Since it uses the same algorithm as WEP, (RC4), existing equipment could be easily upgraded with just a firmware/software update. A long-term solution WPA2 PSK (AES) was created as well.

WPA-PSK (TKIP) is still far, far better than WEP by many order of magintude, but WPA2-PSK is better, and if all you wireless devices support it (in particular the Nintendo DS DOES NOT, The DSi does, but not for DS games), then that preferred.

Fourth Law of Thermdynamics: There's always more entropy then you think there is, even when you take into account the Fourth Law of Thermodynamics.

I still wouldn't worry about the heat death of the universe, though, unlike those in the aforementioned link.

Don't confuse ffmpeg with libavcodec. Although libavcodec is part of of the ffmpeg distribution, and is used by many other program (mplayer especially), ffmpeg is more than that.

All this plugin does is speed up loading of Java applets. Its benign, and Sun provides instructions on how to turn it off: http://www.java.com/en/download/help/quickstarter.xml .