Much of what you were looking for has recently been added to the Community.
Read/Unread with the ability to mark the entire community as read
When you view threads that have changed (new replies and comments), anything new in the thread is highlighted making it SO easy!
We now send emails that notify you of all threads that have changed that you are subscribed to.
We now send emails to notify you of comments made by others on your replies.
We now maintain the search criteria, view and page of results you were on when you go back and forth from reading threads or if you visit other parts of the portal
The entire system is based on Ideas, Problem, Questions etc. If you look around you will already see dozens of Ideas and Problems from customers that have been discussed and resolved in our products all from the Community participation. Its been working out amazingly well.
There are a couple other dozen changes that we have made since we marked the forums read-only. We have gotten incredible feedback which is what we were looking for and dedicated resources to work on that feedback.