forums

This is the million dollar question, I see it time and time again on here and other php coding related sites and forums but I have NEVER seen an answer to it. So I started digging in and studying how some of the big high traffic forums accomplish this feature of showing you which threads have new unread posts in them and it appears that they store the thread ID number into a user cookie. So there would be a cookie with a thread ID of every thread you have read within a certain amount of time. Or something similar to this. I then read on here that cookies can only store X amount of characters,

1)I want to devlop a website that has forums and chat. The chat and forums are linked in some way .Meaning for each thread the users can chat in the chat room for that thread or can post a reply to the forum. I was thinking of using django for forums and twisted for chat thing.Can i combine the two? The chat application devloped using twisted is linked to the forum. 2)If i use twisted and django what kind of web host shold i use while putting by website on web ?Shold i use a VPS? Or can i get a host that supports both? I would not combine the two per se; calls into Django would happen