well, i never made anything like it coase reloading the pages for each user each 5 seconds must be quite a resource eater + it keeps all users sessions alive, even if they left there machine alone (which means you should implement your own sessionmanagement where they can't stay on the same page for X minutes or work with framepages (see below)) and it envolves to much db-trafic to check for new messages etc OR you could use the application-object. But ASP is really not the best technologie to do this !
So i can't give tyou an example.
Now, you want to notify these users.
I've got the impression you wan't to open a new window and display some info there.
I think you can best do this with a piece of javascript you include in the page, if a new message was posted. So this javascript would then open an url(with the message in) in a new window. But popups are annoying and lot of people will use a popupkiller so they wount see the messages + people that disable javascrip also miss out on all the fun (the pages wount reload also)
This is what i would do : create a framepage and have only one frame that displays the message, or that displays a link to the message. And just reload this one frame each 5 seconds (not the framepage itself, only the page in one of the frames). This will generate the least trafic and will work with popupkiller-users.
You can do the same with an iframe, i suppose. So each 5 seconds an ASP page is requested. This pages should then check if there were new messages since the last check from that user.
I suppose you're only interested in the last few messages.
So say that we create an applicationvariable that is an array, that contains the poster + date-time-value of the messagesubmit + the message (or an url to the message) of the last 10 entry's as a pipedelimited string (poster|date|message).
So you could then do something like
your reload code
dim i, locked, arrdata
locked = application("entrys")
i = 0
response.write(<table>
do while i <= 9
arrdata=split(locked(i), "|", -1,1)
response.write("<tr><td>arrdata(0)</td><td> arrdata(1)</td> <td> arrdata(2)</td></tr>
i = i+1
loop
response.write(</table>
to display the last 10 entrys
Note : the second and third cell starts with 2 spaces but they get transformed here.
If you run sessionchecks (for instance when they need to log in or if you use sessionidentifiers etc) -->You should make sure that the framepage is an html-page (.htm or .html extension). This way, the server will create a different session for each frame. If the client leaves his machine alone, the message-frame's session will be kept alive, buth the other frame (your normal page you have now) will timout. I the user (or another user) hits a link or reloads the page, his session will be destroyed and you can redirect him to the homepage (if you run a session-check on top of your pages)