Why is idle machine reported as 1.0 load average?

[B Wooster]

Using uptime, w, and top - I noticed that the current load average is
listed as 1.0 - never falls below 1.0 - even though there is nothing
going on on the machine, and top reports 99.8%+ idle time...

My recollection (and doing some web searches) show that 0.0 was the
load average with nothing going on in the system.

>From the man pages, I learn that uptime gets its numbers from "w",
which has been completely rewritten.
It does not mention anything about starting at 1.0 instead of 0.0 -
anyone has any info on why idle is now showing up as 1.0 load average?
Example top output:
top - 15:08:11 up 13 days, 18:06,  7 users,  load average: 1.00, 1.01, 1.01
Tasks: 228 total,   1 running, 227 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.3% us,  0.3% sy,  0.0% ni, 99.3% id,  0.0% wa,  0.0% hi,  0.0% si

uname: 2.6.10-1.741_FC3 #1 Thu Jan 13 16:38:22 EST 2005 i686 athlon
i386 GNU/Linux