There are still some tweaks to make to this, but slowly as posting happens I'm working out the best ratios. Basically, the homepage lists the latest posted threads by date, which means new content, old content, anything currently happening. What goes on behind the scenes though, is that it stores the latest 100 threads by date, though will only show the top 15. I've only just made this change, that way older threads should always stay off the homepage, and anything recent pushed onto the homepage, hopefully, and I stress HOPEFULLY, within the last days postings. I say that because there is more than 15 new threads posted in a 24hr period, so everything added new should come up, older content not responded to much should fall down and not be seen.
It's slightly complicated behind the scenes, but the idea is to keep the freshest content on the homepage, being the latest thread date posted + that content is being posted upon as well.
Put simply... if a two new threads are posted, one is highly posted upon, the other isn't... the highly posted upon one may spend a little more air time on the homepage than the one not being posted upon. Not much... but a little more air time.