Is it necessary to wait untill no one use a site before updating and republishing it? How can you make sure no one is using the site? Thanks.

I was able to do that (get to know when there is nobody connected)

I have a field in my database called "online" and set it to 0 when the Session_End event take place

The problem is that users can close the browser without logging out and, in that case, their sessions remain alive even though the user is no longer connected.

I've found a solution using Javascript and Framesets, take a look:

http://forums.asp.net/t/1150538.aspx

In my case, I needed to know when there was nobody connected becouse I was woried about the first time compilation being so slow

Good Luck