Listed here are links to various bits and pieces I've put together based on research on QuakeIII Arena usage patterns.
Latency Sensitivity and NAT Usage in Online Games (talk at Marconi Labs, Cambridge, 11/27/01)
Lag over 150 milliseconds is unacceptable (5/17/01, superseded by results presented at IMW2001 workshop above)
Home use and NAT penetration in the QuakeIII Community (5/2/01, includes a different approach to estimating NAT/NAPT penetration. Updated 5/13/01.)
Quake2 packet size distribution (4/6/00) [for old time's sake]
Last updated 1/15/02