MOCA? Using your cable line to carry Ethernet?

So I'm relating to all the discussions of the problems with wireless networks (flakey) for music, but then if you try ethernet over power lines then you will get noise in your power into your stereo, etc....

Kal R of Stereophile (I believe) dropped a hint that he uses "MOCA".

so I googled around, and from what I surmise, MOCA enabled products use your cable line as an ethernet line.

Am I understanding this correctly?
Any of you tried this?
Can Ethernet (post modem) really co-exist on same line with Comcast (pre-modem)?

Sounds too good to be true.

I have not used MOCA but it does intrigue me.

Another alternative to flaky WiFi - particularly with Squeezebox products which are G only, not N - could be a WiFi N adapter like Cisco-Linksys WET610N Dual-Band Wireless-N Adapter. Other vendors sell something like this too. Assuming that the adapter allows for 5Ghz, then that should bypass any local interference at 2.4Ghz.

I need to so something about this flaky WiFi:
Power-line Ethernet?
WIFI N adapter for the SB devices?
sit on the sofa and quietly hum tunes to myself :-o

I am currently using PowerLine ethernet in one system but, in the other, the SBT works fine with wifi.