Your probably right CaptJayJay, it is more personal curiosity.
Thanks for the answers. Some thoughts;
1) Good. Tim91, i just checked and the only mention is that NOTA extends from FL55 upwards, and is Class A
2) Yes, the news report i seem to remember seeing said 2.2 million for 2009
3) I too thought 'Modem S' might be a typo. Cpt. I-DEID your understanding sounds better, in that the TDB contains all the info whereas the Mode(m) S window just shows a specific aircraft. Be nice if a real ATCO could confirm this, or i suppose i could always ask.
4) I had a browse and found a post on flightglobal that said IFACTS actually uses an 18 minute prediction, and was also rolled out in 08/09.
5) I now understand exactly how a stack operates, having used the bible (wikipedia!). It was easier even that i imagined!
Thanks for the help (and good luck to you too
)