It might simply be better to put them in alphabetical order. I'm not really sure what order they're in now. Doing it by productiveness is a nice idea but in practice I think it would cause quite a bit of griping. It'd be better to go with something less biased like a normal ordering like alphabetical, something that can be clearly seen as to how things are ordered.
Chronological however isn't the worst idea and I'm not all ruling that out. Something I think the mods could benefit from however would be a last update date by the name of the mod. That in itself would allow any visitor to the site to see which is the most recent worked on mod. Still the most recent can and never will mean it's the most complete, which is why I don't suggest re-ordering the mod list everytime a mod updates, even if they're not that frequent.
So my final feedback is that it should be in alphabetical and perhaps include two dates. The first date would tell when the mod was originally started (first alpha or beta was released), the second would show the last date of a new version for the mod. This would show immensely how much progress was done in a very clear manner. Either way some clue that a mod 'has' made progress and steady and productive progress at that, should be shown.
Just keep in mind many of the further along mods out now 'will not' work with the version of Notrium on the main page. So until the main page's version reaches 1.34 than all these newer version wont even be playable. For now I think how things are will be fine 'until' 1.34 comes out. The main page itself maybe could use a once over to further clarify there is still at least modding going on after 1.34 is officially released