You can't play on internet without a really really perfectly burned copy and even then you need a serial. I think the problem with AOM is that despite its one of the best games ever:
#1. It has a complex economy which turns alot of people off.
#2. ESO isn't very user friendly and i'm sure many people don't play it on the net.
#3. Warcraft III and C&C Generals took alot of people from ESO and many potential buyers of AOM. Its very competitive and it seems Warcraft III is more popular to the average person but I don't see why.
I also wanna add the replay value for AOM is incredible. Sure its gets boring after 4 straight months of it, but after you leave for a month or two and try other games, it draws you right back. And i'm sure the ex pack is just going to strengthen that.
Pentium 4 2.8 ghz 800 FSB, xfx 7800gt OC 256mb, 1gb ddr2 ram @ 533mhz, 160gb raid 0 HD
Experience is something you don't get until just after you need it.