NZDX Forum Page only shows the Last Day's Posts

Why do NZDX posts only stay visible for 24hrs on the NZDX forum page?
http://www.sharetrader.co.nz/forumdisplay.php?28-NZDX

In all the other forums at least a week or so of recently updated posts are visible. For NZDX this should be more like 3 months considering the more long term/stable nature of bonds etc. Well in theory at least!

There are plenty of valuable threads in the NZDX section that most people probably ignore because they do not show on the forum index page when they click on it unless they happened to have been updated that day.

Apart from that keep up the good work and bring on the iPhone version :)