interpreting uptime output

[Laszlo Nagy]

 From the manual:
> NAME
>      uptime -- show how long system has been running
>
> SYNOPSIS
>      uptime
>
> DESCRIPTION
>      The uptime utility displays the current time, the length of time 
> the sys-
>      tem has been up, the number of users, and the load average of the 
> system
>      over the last 1, 5, and 15 minutes.
This is great, except that it does not tell me what "0.5" means? Example:

 1:41PM  up 5 days,  2:22, 4 users, load averages: 0.36, 0.42, 0.51

The only referenced material in the man page is w(1) which tells this:

 > The load average numbers give the number of jobs in the run queue 
averaged over 1, 5 and 15 minutes.

What are those "jobs"? I guess they are not processes. What is that "run 
queue"? Which is better, the lower or the higher number?

Thanks,

   Laszlo