How do "THEY" decide???

I always like to watch the news on TV... and guess what.....

I was home early today (12-Jan-2010) and I managed to watch the 9pm,10pm and 11pm news on TV but it suddenly strike my mind and I wonder how "THEY" choose the type of important local/overseas news to share with our TV viewers within the short 30 minutes???

I asked because when I checked the C-N-A website, I happened to see some important news that were not highlighted on the TV today:


Then I realized, MUST be either:

• that 3 minutes toilet break that I went today during the news telecast or
• that Monday (11-Jan-2010) blues again. Make me sleep early yesterday
  

and missed out this piece of important news during the 30 minutes highlight on TV.