Uptime command in terminal displays 2 users?

Your machine is special!
Anyways, I sorry that my post aren't clear, english is my second language. My primary language is UNIX.
I thought I'd post a snippet of /private/etc/ttys->

#
# @(#)ttys 5.2 (Berkeley) 6/10/93
#
# name getty type status comments
#
# To secure single-user mode, enable Firmware password protection.
# http://docs.info.apple.com/article.html?artnum=106482
#
#console "/usr/libexec/getty std.57600" vt100 on secure
console "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow" vt100 on secure onoption="/usr/libexec/getty std.9600"

Interestingly, not on my machines:
Last login: Tue May 18 14:32:09 on ttys000

And?

FWIW,

console "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow" vt100 on secure onoption="/usr/libexec/getty std.9600"

Every new Terminal session

+Last login: Tue May 18 15:04:59 on ttys000+
MOTD
+localhost:~ username$+

When you open a new terminal window it shows how the previous session connected. It's a security thing to allow you to spot if somebody is accessing your machine at a time or via a connection you weren't expecting.

When you first login, that session connects via "console", so your first terminal session will show "console" as the previous connection. However, that terminal session will have connected via "ttys000". The next terminal window to open will therefore show "ttys000".

If you open two or more terminal sessions at the same time then subsequent "ttys" are used - "ttys001", "ttys002" and so on. Once you close a terminal session, it's "ttys" device becomes available for re-use.

Hope that's a bit clearer than mud!

I have similar problem, I have fear about I have some intrusion...
my firewall ask new for allow services connect to internet that never before asked me!!!
I typing in terminal ''ac -p'' and I get:
Guest 1.94
root 0.37
Juan 1868.93
total 1871.24

It is mean I have an active connection from a Guest?? I didn't allow guest accounts in my system, then... any idea what happens?

If I reinstall leopard and use last timemachine files I will have a clean operate system to start from zero?

Uptime always displays that message. If I recall the second user is the "system" user.

Does anyone know why it would register 2 users when I am the only user and there are no other accounts enabled

Type ->

who

This will reveal the users.

The "console" one is your main login session in OS X. The "ttys000" one is your session in the terminal.

If you opened a second terminal window then that session would be "ttys001" and so on.

*ac -p*

reveals all users currently logged in. For single-user machines, that will be you and root (i.e., the system).

Thank Mudge for his excellent explanation. What is really confusing is when you start the first terminal session it reports Login: ********** *** on console.

Interestingly, not on my machines:

*Last login: Tue May 18 14:32:09 on ttys000*

Again, you are right on. I hope that others can understand your post.