How do you know? Do you have special info? Our (admitted) speculations on Steam are based on experience with Steam thus far and their own admissions that the release didn't go well and that they had "catastrophically underestimated" community demand
well let's see... we go to school for something:
average kb/s "required" per user for HL2 release let's say 100kb/s
100mbit is about 12,500kb/s max capacity (theoretically speaking)
they have about 28 of those if most of them are up (some of them are not 100mbit, in reality there are 31 servers when i write this.)
12,500kb/s * 28 = 350,000kb/s
number of ppl that will buy HL2 over steam... well i have no idea so i'm just gonna use a round figure to make it easy to estimate: 50,000ppl
50,000ppl * 100kb/s
5,000,000 kb/s
the game, assuming it's 2 cd's worth, is 1,200,000kb, would take about 3-4 hours to download
total steam bandwidth 350,000kb/s compared to:
50,000ppl -> 5,000,000kb/s
100,000ppl -> 10,000,000kb/s
200,000ppl -> 20,000,000kb/s
500,000ppl -> 50,000,000kb/s
1,000,000ppl -> 100,000,000kb/s
course a million people won't download the game at the same time (or will they? heh heh)
valve thought it could handle THIS community