CMOS...floating inputs

[jrcfg]

I have read many times in various forums that allowing an input to float is a bad idea...that unused inputs should be pulled up or down.  I always do just that as a result. 

Just so I know.... why, specifically, is it a bad idea to float a CMOS input??

And feel free to get technical.... ;D

[audioguru]

Hi Jrcfg,
A Cmos input has an extremely high resistance and will:
1) Get damaged by any nearby static electricity.
2) Capacitively pick-up nearby signals resulting in a wrong or random output.
3) Maybe oscillate at a very high frequency if it picks-up its own output.
4) Dissipate power because it operates linear instead of logic switching. ;D

I only used a little geek-talk!