Thread meaning: Games for Windows/LIVE is now free.
Games for Windows is JUST like LIVE except its for the PC, even though they're both the same thing except different systems. It allows you to play 360 gamers on the PC.
Lets say for example Bob is playing Halo 2 on his 360. Bob wants to play Halo 2 with Jeff, but Jeff doesn't have an Xbox or a 360, only a PC with Windows Live and Vista. Jeff also has Halo 2 but for Vista. He plays Halo 2 on his PC, and through Windows Live he is able to play with Bob, even though they're on different systems. This only works on PC games supported by Games for Windows that are also on 360.
What the topic starter is saying is that both LIVE and Windows Live are free, possibly including Gold subscription as far as I know. This means you no longer have to pay to play online on Games for Windows or Xbox Live.
tl;dr:
first paragraph: Games for Windows Live is like Xbox LIVE except for PC, even though they're both on different systems.
second paragraph: Both Games for Windows Live and Xbox LIVE are totally free. You can play multiplayer as much as you want.
osht edit: Very important:
Playing LIVE is now free on PC, but it still costs money on the Xbox.
byebye tf2 on 360, at least I can look forward to H2V.

If multiplayer is internet, shouldn't we be able to play online freely without charge?